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Btrfs: introduce per-subvolume delalloc inode list
[linux-2.6-block.git] / fs / btrfs / relocation.c
CommitLineData
5d4f98a2
YZ		 1/*
2 * Copyright (C) 2009 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19#include <linux/sched.h>
20#include <linux/pagemap.h>
21#include <linux/writeback.h>
22#include <linux/blkdev.h>
23#include <linux/rbtree.h>
5a0e3ad6 24#include <linux/slab.h>
5d4f98a2
YZ		 25#include "ctree.h"
26#include "disk-io.h"
27#include "transaction.h"
28#include "volumes.h"
29#include "locking.h"
30#include "btrfs_inode.h"
31#include "async-thread.h"
0af3d00b 32#include "free-space-cache.h"
581bb050 33#include "inode-map.h"
5d4f98a2
YZ		 34
35/*
36 * backref_node, mapping_node and tree_block start with this
37 */
38struct tree_entry {
39 struct rb_node rb_node;
40 u64 bytenr;
41};
42
43/*
44 * present a tree block in the backref cache
45 */
46struct backref_node {
47 struct rb_node rb_node;
48 u64 bytenr;
3fd0a558
YZ		 49
50 u64 new_bytenr;
51 /* objectid of tree block owner, can be not uptodate */
5d4f98a2 52 u64 owner;
3fd0a558
YZ		 53 /* link to pending, changed or detached list */
54 struct list_head list;
5d4f98a2
YZ		 55 /* list of upper level blocks reference this block */
56 struct list_head upper;
57 /* list of child blocks in the cache */
58 struct list_head lower;
59 /* NULL if this node is not tree root */
60 struct btrfs_root *root;
61 /* extent buffer got by COW the block */
62 struct extent_buffer *eb;
63 /* level of tree block */
64 unsigned int level:8;
3fd0a558
YZ		 65 /* is the block in non-reference counted tree */
66 unsigned int cowonly:1;
67 /* 1 if no child node in the cache */
5d4f98a2
YZ		 68 unsigned int lowest:1;
69 /* is the extent buffer locked */
70 unsigned int locked:1;
71 /* has the block been processed */
72 unsigned int processed:1;
73 /* have backrefs of this block been checked */
74 unsigned int checked:1;
3fd0a558
YZ		 75 /*
76 * 1 if corresponding block has been cowed but some upper
77 * level block pointers may not point to the new location
78 */
79 unsigned int pending:1;
80 /*
81 * 1 if the backref node isn't connected to any other
82 * backref node.
83 */
84 unsigned int detached:1;
5d4f98a2
YZ		 85};
86
87/*
88 * present a block pointer in the backref cache
89 */
90struct backref_edge {
91 struct list_head list[2];
92 struct backref_node *node[2];
5d4f98a2
YZ		 93};
94
95#define LOWER 0
96#define UPPER 1
97
98struct backref_cache {
99 /* red black tree of all backref nodes in the cache */
100 struct rb_root rb_root;
3fd0a558
YZ		 101 /* for passing backref nodes to btrfs_reloc_cow_block */
102 struct backref_node *path[BTRFS_MAX_LEVEL];
103 /*
104 * list of blocks that have been cowed but some block
105 * pointers in upper level blocks may not reflect the
106 * new location
107 */
5d4f98a2 108 struct list_head pending[BTRFS_MAX_LEVEL];
3fd0a558
YZ		 109 /* list of backref nodes with no child node */
110 struct list_head leaves;
111 /* list of blocks that have been cowed in current transaction */
112 struct list_head changed;
113 /* list of detached backref node. */
114 struct list_head detached;
115
116 u64 last_trans;
117
118 int nr_nodes;
119 int nr_edges;
5d4f98a2
YZ		 120};
121
122/*
123 * map address of tree root to tree
124 */
125struct mapping_node {
126 struct rb_node rb_node;
127 u64 bytenr;
128 void *data;
129};
130
131struct mapping_tree {
132 struct rb_root rb_root;
133 spinlock_t lock;
134};
135
136/*
137 * present a tree block to process
138 */
139struct tree_block {
140 struct rb_node rb_node;
141 u64 bytenr;
142 struct btrfs_key key;
143 unsigned int level:8;
144 unsigned int key_ready:1;
145};
146
0257bb82
YZ		 147#define MAX_EXTENTS 128
148
149struct file_extent_cluster {
150 u64 start;
151 u64 end;
152 u64 boundary[MAX_EXTENTS];
153 unsigned int nr;
154};
155
5d4f98a2
YZ		 156struct reloc_control {
157 /* block group to relocate */
158 struct btrfs_block_group_cache *block_group;
159 /* extent tree */
160 struct btrfs_root *extent_root;
161 /* inode for moving data */
162 struct inode *data_inode;
3fd0a558
YZ		 163
164 struct btrfs_block_rsv *block_rsv;
165
166 struct backref_cache backref_cache;
167
168 struct file_extent_cluster cluster;
5d4f98a2
YZ		 169 /* tree blocks have been processed */
170 struct extent_io_tree processed_blocks;
171 /* map start of tree root to corresponding reloc tree */
172 struct mapping_tree reloc_root_tree;
173 /* list of reloc trees */
174 struct list_head reloc_roots;
3fd0a558
YZ		 175 /* size of metadata reservation for merging reloc trees */
176 u64 merging_rsv_size;
177 /* size of relocated tree nodes */
178 u64 nodes_relocated;
179
5d4f98a2
YZ		 180 u64 search_start;
181 u64 extents_found;
3fd0a558 182
3fd0a558
YZ		 183 unsigned int stage:8;
184 unsigned int create_reloc_tree:1;
185 unsigned int merge_reloc_tree:1;
5d4f98a2 186 unsigned int found_file_extent:1;
3fd0a558 187 unsigned int commit_transaction:1;
5d4f98a2
YZ		 188};
189
190/* stages of data relocation */
191#define MOVE_DATA_EXTENTS 0
192#define UPDATE_DATA_PTRS 1
193
3fd0a558
YZ		 194static void remove_backref_node(struct backref_cache *cache,
195 struct backref_node *node);
196static void __mark_block_processed(struct reloc_control *rc,
197 struct backref_node *node);
5d4f98a2
YZ		 198
199static void mapping_tree_init(struct mapping_tree *tree)
200{
6bef4d31 201 tree->rb_root = RB_ROOT;
5d4f98a2
YZ		 202 spin_lock_init(&tree->lock);
203}
204
205static void backref_cache_init(struct backref_cache *cache)
206{
207 int i;
6bef4d31 208 cache->rb_root = RB_ROOT;
5d4f98a2
YZ		 209 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
210 INIT_LIST_HEAD(&cache->pending[i]);
3fd0a558
YZ		 211 INIT_LIST_HEAD(&cache->changed);
212 INIT_LIST_HEAD(&cache->detached);
213 INIT_LIST_HEAD(&cache->leaves);
214}
215
216static void backref_cache_cleanup(struct backref_cache *cache)
217{
218 struct backref_node *node;
219 int i;
220
221 while (!list_empty(&cache->detached)) {
222 node = list_entry(cache->detached.next,
223 struct backref_node, list);
224 remove_backref_node(cache, node);
225 }
226
227 while (!list_empty(&cache->leaves)) {
228 node = list_entry(cache->leaves.next,
229 struct backref_node, lower);
230 remove_backref_node(cache, node);
231 }
232
233 cache->last_trans = 0;
234
235 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
236 BUG_ON(!list_empty(&cache->pending[i]));
237 BUG_ON(!list_empty(&cache->changed));
238 BUG_ON(!list_empty(&cache->detached));
239 BUG_ON(!RB_EMPTY_ROOT(&cache->rb_root));
240 BUG_ON(cache->nr_nodes);
241 BUG_ON(cache->nr_edges);
242}
243
244static struct backref_node *alloc_backref_node(struct backref_cache *cache)
245{
246 struct backref_node *node;
247
248 node = kzalloc(sizeof(*node), GFP_NOFS);
249 if (node) {
250 INIT_LIST_HEAD(&node->list);
251 INIT_LIST_HEAD(&node->upper);
252 INIT_LIST_HEAD(&node->lower);
253 RB_CLEAR_NODE(&node->rb_node);
254 cache->nr_nodes++;
255 }
256 return node;
257}
258
259static void free_backref_node(struct backref_cache *cache,
260 struct backref_node *node)
261{
262 if (node) {
263 cache->nr_nodes--;
264 kfree(node);
265 }
266}
267
268static struct backref_edge *alloc_backref_edge(struct backref_cache *cache)
269{
270 struct backref_edge *edge;
271
272 edge = kzalloc(sizeof(*edge), GFP_NOFS);
273 if (edge)
274 cache->nr_edges++;
275 return edge;
5d4f98a2
YZ		 276}
277
3fd0a558
YZ		 278static void free_backref_edge(struct backref_cache *cache,
279 struct backref_edge *edge)
5d4f98a2 280{
3fd0a558
YZ		 281 if (edge) {
282 cache->nr_edges--;
283 kfree(edge);
284 }
5d4f98a2
YZ		 285}
286
287static struct rb_node *tree_insert(struct rb_root *root, u64 bytenr,
288 struct rb_node *node)
289{
290 struct rb_node **p = &root->rb_node;
291 struct rb_node *parent = NULL;
292 struct tree_entry *entry;
293
294 while (*p) {
295 parent = *p;
296 entry = rb_entry(parent, struct tree_entry, rb_node);
297
298 if (bytenr < entry->bytenr)
299 p = &(*p)->rb_left;
300 else if (bytenr > entry->bytenr)
301 p = &(*p)->rb_right;
302 else
303 return parent;
304 }
305
306 rb_link_node(node, parent, p);
307 rb_insert_color(node, root);
308 return NULL;
309}
310
311static struct rb_node *tree_search(struct rb_root *root, u64 bytenr)
312{
313 struct rb_node *n = root->rb_node;
314 struct tree_entry *entry;
315
316 while (n) {
317 entry = rb_entry(n, struct tree_entry, rb_node);
318
319 if (bytenr < entry->bytenr)
320 n = n->rb_left;
321 else if (bytenr > entry->bytenr)
322 n = n->rb_right;
323 else
324 return n;
325 }
326 return NULL;
327}
328
48a3b636 329static void backref_tree_panic(struct rb_node *rb_node, int errno, u64 bytenr)
43c04fb1
JM		 330{
331
332 struct btrfs_fs_info *fs_info = NULL;
333 struct backref_node *bnode = rb_entry(rb_node, struct backref_node,
334 rb_node);
335 if (bnode->root)
336 fs_info = bnode->root->fs_info;
337 btrfs_panic(fs_info, errno, "Inconsistency in backref cache "
338 "found at offset %llu\n", (unsigned long long)bytenr);
339}
340
5d4f98a2
YZ		 341/*
342 * walk up backref nodes until reach node presents tree root
343 */
344static struct backref_node *walk_up_backref(struct backref_node *node,
345 struct backref_edge *edges[],
346 int *index)
347{
348 struct backref_edge *edge;
349 int idx = *index;
350
351 while (!list_empty(&node->upper)) {
352 edge = list_entry(node->upper.next,
353 struct backref_edge, list[LOWER]);
354 edges[idx++] = edge;
355 node = edge->node[UPPER];
356 }
3fd0a558 357 BUG_ON(node->detached);
5d4f98a2
YZ		 358 *index = idx;
359 return node;
360}
361
362/*
363 * walk down backref nodes to find start of next reference path
364 */
365static struct backref_node *walk_down_backref(struct backref_edge *edges[],
366 int *index)
367{
368 struct backref_edge *edge;
369 struct backref_node *lower;
370 int idx = *index;
371
372 while (idx > 0) {
373 edge = edges[idx - 1];
374 lower = edge->node[LOWER];
375 if (list_is_last(&edge->list[LOWER], &lower->upper)) {
376 idx--;
377 continue;
378 }
379 edge = list_entry(edge->list[LOWER].next,
380 struct backref_edge, list[LOWER]);
381 edges[idx - 1] = edge;
382 *index = idx;
383 return edge->node[UPPER];
384 }
385 *index = 0;
386 return NULL;
387}
388
3fd0a558
YZ		 389static void unlock_node_buffer(struct backref_node *node)
390{
391 if (node->locked) {
392 btrfs_tree_unlock(node->eb);
393 node->locked = 0;
394 }
395}
396
5d4f98a2
YZ		 397static void drop_node_buffer(struct backref_node *node)
398{
399 if (node->eb) {
3fd0a558 400 unlock_node_buffer(node);
5d4f98a2
YZ		 401 free_extent_buffer(node->eb);
402 node->eb = NULL;
403 }
404}
405
406static void drop_backref_node(struct backref_cache *tree,
407 struct backref_node *node)
408{
5d4f98a2
YZ		 409 BUG_ON(!list_empty(&node->upper));
410
411 drop_node_buffer(node);
3fd0a558 412 list_del(&node->list);
5d4f98a2 413 list_del(&node->lower);
3fd0a558
YZ		 414 if (!RB_EMPTY_NODE(&node->rb_node))
415 rb_erase(&node->rb_node, &tree->rb_root);
416 free_backref_node(tree, node);
5d4f98a2
YZ		 417}
418
419/*
420 * remove a backref node from the backref cache
421 */
422static void remove_backref_node(struct backref_cache *cache,
423 struct backref_node *node)
424{
425 struct backref_node *upper;
426 struct backref_edge *edge;
427
428 if (!node)
429 return;
430
3fd0a558 431 BUG_ON(!node->lowest && !node->detached);
5d4f98a2
YZ		 432 while (!list_empty(&node->upper)) {
433 edge = list_entry(node->upper.next, struct backref_edge,
434 list[LOWER]);
435 upper = edge->node[UPPER];
436 list_del(&edge->list[LOWER]);
437 list_del(&edge->list[UPPER]);
3fd0a558
YZ		 438 free_backref_edge(cache, edge);
439
440 if (RB_EMPTY_NODE(&upper->rb_node)) {
441 BUG_ON(!list_empty(&node->upper));
442 drop_backref_node(cache, node);
443 node = upper;
444 node->lowest = 1;
445 continue;
446 }
5d4f98a2 447 /*
3fd0a558 448 * add the node to leaf node list if no other
5d4f98a2
YZ		 449 * child block cached.
450 */
451 if (list_empty(&upper->lower)) {
3fd0a558 452 list_add_tail(&upper->lower, &cache->leaves);
5d4f98a2
YZ		 453 upper->lowest = 1;
454 }
455 }
3fd0a558 456
5d4f98a2
YZ		 457 drop_backref_node(cache, node);
458}
459
3fd0a558
YZ		 460static void update_backref_node(struct backref_cache *cache,
461 struct backref_node *node, u64 bytenr)
462{
463 struct rb_node *rb_node;
464 rb_erase(&node->rb_node, &cache->rb_root);
465 node->bytenr = bytenr;
466 rb_node = tree_insert(&cache->rb_root, node->bytenr, &node->rb_node);
43c04fb1
JM		 467 if (rb_node)
468 backref_tree_panic(rb_node, -EEXIST, bytenr);
3fd0a558
YZ		 469}
470
471/*
472 * update backref cache after a transaction commit
473 */
474static int update_backref_cache(struct btrfs_trans_handle *trans,
475 struct backref_cache *cache)
476{
477 struct backref_node *node;
478 int level = 0;
479
480 if (cache->last_trans == 0) {
481 cache->last_trans = trans->transid;
482 return 0;
483 }
484
485 if (cache->last_trans == trans->transid)
486 return 0;
487
488 /*
489 * detached nodes are used to avoid unnecessary backref
490 * lookup. transaction commit changes the extent tree.
491 * so the detached nodes are no longer useful.
492 */
493 while (!list_empty(&cache->detached)) {
494 node = list_entry(cache->detached.next,
495 struct backref_node, list);
496 remove_backref_node(cache, node);
497 }
498
499 while (!list_empty(&cache->changed)) {
500 node = list_entry(cache->changed.next,
501 struct backref_node, list);
502 list_del_init(&node->list);
503 BUG_ON(node->pending);
504 update_backref_node(cache, node, node->new_bytenr);
505 }
506
507 /*
508 * some nodes can be left in the pending list if there were
509 * errors during processing the pending nodes.
510 */
511 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
512 list_for_each_entry(node, &cache->pending[level], list) {
513 BUG_ON(!node->pending);
514 if (node->bytenr == node->new_bytenr)
515 continue;
516 update_backref_node(cache, node, node->new_bytenr);
517 }
518 }
519
520 cache->last_trans = 0;
521 return 1;
522}
523
f2a97a9d 524
3fd0a558
YZ		 525static int should_ignore_root(struct btrfs_root *root)
526{
527 struct btrfs_root *reloc_root;
528
529 if (!root->ref_cows)
530 return 0;
531
532 reloc_root = root->reloc_root;
533 if (!reloc_root)
534 return 0;
535
536 if (btrfs_root_last_snapshot(&reloc_root->root_item) ==
537 root->fs_info->running_transaction->transid - 1)
538 return 0;
539 /*
540 * if there is reloc tree and it was created in previous
541 * transaction backref lookup can find the reloc tree,
542 * so backref node for the fs tree root is useless for
543 * relocation.
544 */
545 return 1;
546}
5d4f98a2
YZ		 547/*
548 * find reloc tree by address of tree root
549 */
550static struct btrfs_root *find_reloc_root(struct reloc_control *rc,
551 u64 bytenr)
552{
553 struct rb_node *rb_node;
554 struct mapping_node *node;
555 struct btrfs_root *root = NULL;
556
557 spin_lock(&rc->reloc_root_tree.lock);
558 rb_node = tree_search(&rc->reloc_root_tree.rb_root, bytenr);
559 if (rb_node) {
560 node = rb_entry(rb_node, struct mapping_node, rb_node);
561 root = (struct btrfs_root *)node->data;
562 }
563 spin_unlock(&rc->reloc_root_tree.lock);
564 return root;
565}
566
567static int is_cowonly_root(u64 root_objectid)
568{
569 if (root_objectid == BTRFS_ROOT_TREE_OBJECTID ||
570 root_objectid == BTRFS_EXTENT_TREE_OBJECTID ||
571 root_objectid == BTRFS_CHUNK_TREE_OBJECTID ||
572 root_objectid == BTRFS_DEV_TREE_OBJECTID ||
573 root_objectid == BTRFS_TREE_LOG_OBJECTID ||
574 root_objectid == BTRFS_CSUM_TREE_OBJECTID)
575 return 1;
576 return 0;
577}
578
579static struct btrfs_root *read_fs_root(struct btrfs_fs_info *fs_info,
580 u64 root_objectid)
581{
582 struct btrfs_key key;
583
584 key.objectid = root_objectid;
585 key.type = BTRFS_ROOT_ITEM_KEY;
586 if (is_cowonly_root(root_objectid))
587 key.offset = 0;
588 else
589 key.offset = (u64)-1;
590
591 return btrfs_read_fs_root_no_name(fs_info, &key);
592}
593
594#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
595static noinline_for_stack
596struct btrfs_root *find_tree_root(struct reloc_control *rc,
597 struct extent_buffer *leaf,
598 struct btrfs_extent_ref_v0 *ref0)
599{
600 struct btrfs_root *root;
601 u64 root_objectid = btrfs_ref_root_v0(leaf, ref0);
602 u64 generation = btrfs_ref_generation_v0(leaf, ref0);
603
604 BUG_ON(root_objectid == BTRFS_TREE_RELOC_OBJECTID);
605
606 root = read_fs_root(rc->extent_root->fs_info, root_objectid);
607 BUG_ON(IS_ERR(root));
608
609 if (root->ref_cows &&
610 generation != btrfs_root_generation(&root->root_item))
611 return NULL;
612
613 return root;
614}
615#endif
616
617static noinline_for_stack
618int find_inline_backref(struct extent_buffer *leaf, int slot,
619 unsigned long *ptr, unsigned long *end)
620{
3173a18f 621 struct btrfs_key key;
5d4f98a2
YZ		 622 struct btrfs_extent_item *ei;
623 struct btrfs_tree_block_info *bi;
624 u32 item_size;
625
3173a18f
JB		 626 btrfs_item_key_to_cpu(leaf, &key, slot);
627
5d4f98a2
YZ		 628 item_size = btrfs_item_size_nr(leaf, slot);
629#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
630 if (item_size < sizeof(*ei)) {
631 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
632 return 1;
633 }
634#endif
635 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
636 WARN_ON(!(btrfs_extent_flags(leaf, ei) &
637 BTRFS_EXTENT_FLAG_TREE_BLOCK));
638
3173a18f
JB		 639 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
640 item_size <= sizeof(*ei) + sizeof(*bi)) {
5d4f98a2
YZ		 641 WARN_ON(item_size < sizeof(*ei) + sizeof(*bi));
642 return 1;
643 }
644
3173a18f
JB		 645 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
646 bi = (struct btrfs_tree_block_info *)(ei + 1);
647 *ptr = (unsigned long)(bi + 1);
648 } else {
649 *ptr = (unsigned long)(ei + 1);
650 }
5d4f98a2
YZ		 651 *end = (unsigned long)ei + item_size;
652 return 0;
653}
654
655/*
656 * build backref tree for a given tree block. root of the backref tree
657 * corresponds the tree block, leaves of the backref tree correspond
658 * roots of b-trees that reference the tree block.
659 *
660 * the basic idea of this function is check backrefs of a given block
661 * to find upper level blocks that refernece the block, and then check
662 * bakcrefs of these upper level blocks recursively. the recursion stop
663 * when tree root is reached or backrefs for the block is cached.
664 *
665 * NOTE: if we find backrefs for a block are cached, we know backrefs
666 * for all upper level blocks that directly/indirectly reference the
667 * block are also cached.
668 */
3fd0a558
YZ		 669static noinline_for_stack
670struct backref_node *build_backref_tree(struct reloc_control *rc,
671 struct btrfs_key *node_key,
672 int level, u64 bytenr)
5d4f98a2 673{
3fd0a558 674 struct backref_cache *cache = &rc->backref_cache;
5d4f98a2
YZ		 675 struct btrfs_path *path1;
676 struct btrfs_path *path2;
677 struct extent_buffer *eb;
678 struct btrfs_root *root;
679 struct backref_node *cur;
680 struct backref_node *upper;
681 struct backref_node *lower;
682 struct backref_node *node = NULL;
683 struct backref_node *exist = NULL;
684 struct backref_edge *edge;
685 struct rb_node *rb_node;
686 struct btrfs_key key;
687 unsigned long end;
688 unsigned long ptr;
689 LIST_HEAD(list);
3fd0a558
YZ		 690 LIST_HEAD(useless);
691 int cowonly;
5d4f98a2
YZ		 692 int ret;
693 int err = 0;
694
695 path1 = btrfs_alloc_path();
696 path2 = btrfs_alloc_path();
697 if (!path1 || !path2) {
698 err = -ENOMEM;
699 goto out;
700 }
026fd317
JB		 701 path1->reada = 1;
702 path2->reada = 2;
5d4f98a2 703
3fd0a558 704 node = alloc_backref_node(cache);
5d4f98a2
YZ		 705 if (!node) {
706 err = -ENOMEM;
707 goto out;
708 }
709
5d4f98a2 710 node->bytenr = bytenr;
5d4f98a2
YZ		 711 node->level = level;
712 node->lowest = 1;
713 cur = node;
714again:
715 end = 0;
716 ptr = 0;
717 key.objectid = cur->bytenr;
3173a18f 718 key.type = BTRFS_METADATA_ITEM_KEY;
5d4f98a2
YZ		 719 key.offset = (u64)-1;
720
721 path1->search_commit_root = 1;
722 path1->skip_locking = 1;
723 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path1,
724 0, 0);
725 if (ret < 0) {
726 err = ret;
727 goto out;
728 }
729 BUG_ON(!ret || !path1->slots[0]);
730
731 path1->slots[0]--;
732
733 WARN_ON(cur->checked);
734 if (!list_empty(&cur->upper)) {
735 /*
70f23fd6 736 * the backref was added previously when processing
5d4f98a2
YZ		 737 * backref of type BTRFS_TREE_BLOCK_REF_KEY
738 */
739 BUG_ON(!list_is_singular(&cur->upper));
740 edge = list_entry(cur->upper.next, struct backref_edge,
741 list[LOWER]);
742 BUG_ON(!list_empty(&edge->list[UPPER]));
743 exist = edge->node[UPPER];
744 /*
745 * add the upper level block to pending list if we need
746 * check its backrefs
747 */
748 if (!exist->checked)
749 list_add_tail(&edge->list[UPPER], &list);
750 } else {
751 exist = NULL;
752 }
753
754 while (1) {
755 cond_resched();
756 eb = path1->nodes[0];
757
758 if (ptr >= end) {
759 if (path1->slots[0] >= btrfs_header_nritems(eb)) {
760 ret = btrfs_next_leaf(rc->extent_root, path1);
761 if (ret < 0) {
762 err = ret;
763 goto out;
764 }
765 if (ret > 0)
766 break;
767 eb = path1->nodes[0];
768 }
769
770 btrfs_item_key_to_cpu(eb, &key, path1->slots[0]);
771 if (key.objectid != cur->bytenr) {
772 WARN_ON(exist);
773 break;
774 }
775
3173a18f
JB		 776 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
777 key.type == BTRFS_METADATA_ITEM_KEY) {
5d4f98a2
YZ		 778 ret = find_inline_backref(eb, path1->slots[0],
779 &ptr, &end);
780 if (ret)
781 goto next;
782 }
783 }
784
785 if (ptr < end) {
786 /* update key for inline back ref */
787 struct btrfs_extent_inline_ref *iref;
788 iref = (struct btrfs_extent_inline_ref *)ptr;
789 key.type = btrfs_extent_inline_ref_type(eb, iref);
790 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
791 WARN_ON(key.type != BTRFS_TREE_BLOCK_REF_KEY &&
792 key.type != BTRFS_SHARED_BLOCK_REF_KEY);
793 }
794
795 if (exist &&
796 ((key.type == BTRFS_TREE_BLOCK_REF_KEY &&
797 exist->owner == key.offset) ||
798 (key.type == BTRFS_SHARED_BLOCK_REF_KEY &&
799 exist->bytenr == key.offset))) {
800 exist = NULL;
801 goto next;
802 }
803
804#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
805 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY ||
806 key.type == BTRFS_EXTENT_REF_V0_KEY) {
3fd0a558 807 if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
5d4f98a2
YZ		 808 struct btrfs_extent_ref_v0 *ref0;
809 ref0 = btrfs_item_ptr(eb, path1->slots[0],
810 struct btrfs_extent_ref_v0);
3fd0a558 811 if (key.objectid == key.offset) {
046f264f 812 root = find_tree_root(rc, eb, ref0);
3fd0a558
YZ		 813 if (root && !should_ignore_root(root))
814 cur->root = root;
815 else
816 list_add(&cur->list, &useless);
817 break;
818 }
046f264f
YZ		 819 if (is_cowonly_root(btrfs_ref_root_v0(eb,
820 ref0)))
821 cur->cowonly = 1;
5d4f98a2
YZ		 822 }
823#else
824 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
825 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) {
826#endif
827 if (key.objectid == key.offset) {
828 /*
829 * only root blocks of reloc trees use
830 * backref of this type.
831 */
832 root = find_reloc_root(rc, cur->bytenr);
833 BUG_ON(!root);
834 cur->root = root;
835 break;
836 }
837
3fd0a558 838 edge = alloc_backref_edge(cache);
5d4f98a2
YZ		 839 if (!edge) {
840 err = -ENOMEM;
841 goto out;
842 }
843 rb_node = tree_search(&cache->rb_root, key.offset);
844 if (!rb_node) {
3fd0a558 845 upper = alloc_backref_node(cache);
5d4f98a2 846 if (!upper) {
3fd0a558 847 free_backref_edge(cache, edge);
5d4f98a2
YZ		 848 err = -ENOMEM;
849 goto out;
850 }
5d4f98a2 851 upper->bytenr = key.offset;
5d4f98a2
YZ		 852 upper->level = cur->level + 1;
853 /*
854 * backrefs for the upper level block isn't
855 * cached, add the block to pending list
856 */
857 list_add_tail(&edge->list[UPPER], &list);
858 } else {
859 upper = rb_entry(rb_node, struct backref_node,
860 rb_node);
3fd0a558 861 BUG_ON(!upper->checked);
5d4f98a2
YZ		 862 INIT_LIST_HEAD(&edge->list[UPPER]);
863 }
3fd0a558 864 list_add_tail(&edge->list[LOWER], &cur->upper);
5d4f98a2 865 edge->node[LOWER] = cur;
3fd0a558 866 edge->node[UPPER] = upper;
5d4f98a2
YZ		 867
868 goto next;
869 } else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) {
870 goto next;
871 }
872
873 /* key.type == BTRFS_TREE_BLOCK_REF_KEY */
874 root = read_fs_root(rc->extent_root->fs_info, key.offset);
875 if (IS_ERR(root)) {
876 err = PTR_ERR(root);
877 goto out;
878 }
879
3fd0a558
YZ		 880 if (!root->ref_cows)
881 cur->cowonly = 1;
882
5d4f98a2
YZ		 883 if (btrfs_root_level(&root->root_item) == cur->level) {
884 /* tree root */
885 BUG_ON(btrfs_root_bytenr(&root->root_item) !=
886 cur->bytenr);
3fd0a558
YZ		 887 if (should_ignore_root(root))
888 list_add(&cur->list, &useless);
889 else
890 cur->root = root;
5d4f98a2
YZ		 891 break;
892 }
893
894 level = cur->level + 1;
895
896 /*
897 * searching the tree to find upper level blocks
898 * reference the block.
899 */
900 path2->search_commit_root = 1;
901 path2->skip_locking = 1;
902 path2->lowest_level = level;
903 ret = btrfs_search_slot(NULL, root, node_key, path2, 0, 0);
904 path2->lowest_level = 0;
905 if (ret < 0) {
906 err = ret;
907 goto out;
908 }
33c66f43
YZ		 909 if (ret > 0 && path2->slots[level] > 0)
910 path2->slots[level]--;
5d4f98a2
YZ		 911
912 eb = path2->nodes[level];
913 WARN_ON(btrfs_node_blockptr(eb, path2->slots[level]) !=
914 cur->bytenr);
915
916 lower = cur;
917 for (; level < BTRFS_MAX_LEVEL; level++) {
918 if (!path2->nodes[level]) {
919 BUG_ON(btrfs_root_bytenr(&root->root_item) !=
920 lower->bytenr);
3fd0a558
YZ		 921 if (should_ignore_root(root))
922 list_add(&lower->list, &useless);
923 else
924 lower->root = root;
5d4f98a2
YZ		 925 break;
926 }
927
3fd0a558 928 edge = alloc_backref_edge(cache);
5d4f98a2
YZ		 929 if (!edge) {
930 err = -ENOMEM;
931 goto out;
932 }
933
934 eb = path2->nodes[level];
935 rb_node = tree_search(&cache->rb_root, eb->start);
936 if (!rb_node) {
3fd0a558 937 upper = alloc_backref_node(cache);
5d4f98a2 938 if (!upper) {
3fd0a558 939 free_backref_edge(cache, edge);
5d4f98a2
YZ		 940 err = -ENOMEM;
941 goto out;
942 }
5d4f98a2
YZ		 943 upper->bytenr = eb->start;
944 upper->owner = btrfs_header_owner(eb);
945 upper->level = lower->level + 1;
3fd0a558
YZ		 946 if (!root->ref_cows)
947 upper->cowonly = 1;
5d4f98a2
YZ		 948
949 /*
950 * if we know the block isn't shared
951 * we can void checking its backrefs.
952 */
953 if (btrfs_block_can_be_shared(root, eb))
954 upper->checked = 0;
955 else
956 upper->checked = 1;
957
958 /*
959 * add the block to pending list if we
960 * need check its backrefs. only block
961 * at 'cur->level + 1' is added to the
962 * tail of pending list. this guarantees
963 * we check backrefs from lower level
964 * blocks to upper level blocks.
965 */
966 if (!upper->checked &&
967 level == cur->level + 1) {
968 list_add_tail(&edge->list[UPPER],
969 &list);
970 } else
971 INIT_LIST_HEAD(&edge->list[UPPER]);
972 } else {
973 upper = rb_entry(rb_node, struct backref_node,
974 rb_node);
975 BUG_ON(!upper->checked);
976 INIT_LIST_HEAD(&edge->list[UPPER]);
3fd0a558
YZ		 977 if (!upper->owner)
978 upper->owner = btrfs_header_owner(eb);
5d4f98a2
YZ		 979 }
980 list_add_tail(&edge->list[LOWER], &lower->upper);
5d4f98a2 981 edge->node[LOWER] = lower;
3fd0a558 982 edge->node[UPPER] = upper;
5d4f98a2
YZ		 983
984 if (rb_node)
985 break;
986 lower = upper;
987 upper = NULL;
988 }
b3b4aa74 989 btrfs_release_path(path2);
5d4f98a2
YZ		 990next:
991 if (ptr < end) {
992 ptr += btrfs_extent_inline_ref_size(key.type);
993 if (ptr >= end) {
994 WARN_ON(ptr > end);
995 ptr = 0;
996 end = 0;
997 }
998 }
999 if (ptr >= end)
1000 path1->slots[0]++;
1001 }
b3b4aa74 1002 btrfs_release_path(path1);
5d4f98a2
YZ		 1003
1004 cur->checked = 1;
1005 WARN_ON(exist);
1006
1007 /* the pending list isn't empty, take the first block to process */
1008 if (!list_empty(&list)) {
1009 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1010 list_del_init(&edge->list[UPPER]);
1011 cur = edge->node[UPPER];
1012 goto again;
1013 }
1014
1015 /*
1016 * everything goes well, connect backref nodes and insert backref nodes
1017 * into the cache.
1018 */
1019 BUG_ON(!node->checked);
3fd0a558
YZ		 1020 cowonly = node->cowonly;
1021 if (!cowonly) {
1022 rb_node = tree_insert(&cache->rb_root, node->bytenr,
1023 &node->rb_node);
43c04fb1
JM		 1024 if (rb_node)
1025 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
3fd0a558
YZ		 1026 list_add_tail(&node->lower, &cache->leaves);
1027 }
5d4f98a2
YZ		 1028
1029 list_for_each_entry(edge, &node->upper, list[LOWER])
1030 list_add_tail(&edge->list[UPPER], &list);
1031
1032 while (!list_empty(&list)) {
1033 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1034 list_del_init(&edge->list[UPPER]);
1035 upper = edge->node[UPPER];
3fd0a558
YZ		 1036 if (upper->detached) {
1037 list_del(&edge->list[LOWER]);
1038 lower = edge->node[LOWER];
1039 free_backref_edge(cache, edge);
1040 if (list_empty(&lower->upper))
1041 list_add(&lower->list, &useless);
1042 continue;
1043 }
5d4f98a2
YZ		 1044
1045 if (!RB_EMPTY_NODE(&upper->rb_node)) {
1046 if (upper->lowest) {
1047 list_del_init(&upper->lower);
1048 upper->lowest = 0;
1049 }
1050
1051 list_add_tail(&edge->list[UPPER], &upper->lower);
1052 continue;
1053 }
1054
1055 BUG_ON(!upper->checked);
3fd0a558
YZ		 1056 BUG_ON(cowonly != upper->cowonly);
1057 if (!cowonly) {
1058 rb_node = tree_insert(&cache->rb_root, upper->bytenr,
1059 &upper->rb_node);
43c04fb1
JM		 1060 if (rb_node)
1061 backref_tree_panic(rb_node, -EEXIST,
1062 upper->bytenr);
3fd0a558 1063 }
5d4f98a2
YZ		 1064
1065 list_add_tail(&edge->list[UPPER], &upper->lower);
1066
1067 list_for_each_entry(edge, &upper->upper, list[LOWER])
1068 list_add_tail(&edge->list[UPPER], &list);
1069 }
3fd0a558
YZ		 1070 /*
1071 * process useless backref nodes. backref nodes for tree leaves
1072 * are deleted from the cache. backref nodes for upper level
1073 * tree blocks are left in the cache to avoid unnecessary backref
1074 * lookup.
1075 */
1076 while (!list_empty(&useless)) {
1077 upper = list_entry(useless.next, struct backref_node, list);
1078 list_del_init(&upper->list);
1079 BUG_ON(!list_empty(&upper->upper));
1080 if (upper == node)
1081 node = NULL;
1082 if (upper->lowest) {
1083 list_del_init(&upper->lower);
1084 upper->lowest = 0;
1085 }
1086 while (!list_empty(&upper->lower)) {
1087 edge = list_entry(upper->lower.next,
1088 struct backref_edge, list[UPPER]);
1089 list_del(&edge->list[UPPER]);
1090 list_del(&edge->list[LOWER]);
1091 lower = edge->node[LOWER];
1092 free_backref_edge(cache, edge);
1093
1094 if (list_empty(&lower->upper))
1095 list_add(&lower->list, &useless);
1096 }
1097 __mark_block_processed(rc, upper);
1098 if (upper->level > 0) {
1099 list_add(&upper->list, &cache->detached);
1100 upper->detached = 1;
1101 } else {
1102 rb_erase(&upper->rb_node, &cache->rb_root);
1103 free_backref_node(cache, upper);
1104 }
1105 }
5d4f98a2
YZ		 1106out:
1107 btrfs_free_path(path1);
1108 btrfs_free_path(path2);
1109 if (err) {
3fd0a558
YZ		 1110 while (!list_empty(&useless)) {
1111 lower = list_entry(useless.next,
1112 struct backref_node, upper);
1113 list_del_init(&lower->upper);
1114 }
5d4f98a2 1115 upper = node;
3fd0a558 1116 INIT_LIST_HEAD(&list);
5d4f98a2
YZ		 1117 while (upper) {
1118 if (RB_EMPTY_NODE(&upper->rb_node)) {
1119 list_splice_tail(&upper->upper, &list);
3fd0a558 1120 free_backref_node(cache, upper);
5d4f98a2
YZ		 1121 }
1122
1123 if (list_empty(&list))
1124 break;
1125
1126 edge = list_entry(list.next, struct backref_edge,
1127 list[LOWER]);
3fd0a558 1128 list_del(&edge->list[LOWER]);
5d4f98a2 1129 upper = edge->node[UPPER];
3fd0a558 1130 free_backref_edge(cache, edge);
5d4f98a2
YZ		 1131 }
1132 return ERR_PTR(err);
1133 }
3fd0a558 1134 BUG_ON(node && node->detached);
5d4f98a2
YZ		 1135 return node;
1136}
1137
3fd0a558
YZ		 1138/*
1139 * helper to add backref node for the newly created snapshot.
1140 * the backref node is created by cloning backref node that
1141 * corresponds to root of source tree
1142 */
1143static int clone_backref_node(struct btrfs_trans_handle *trans,
1144 struct reloc_control *rc,
1145 struct btrfs_root *src,
1146 struct btrfs_root *dest)
1147{
1148 struct btrfs_root *reloc_root = src->reloc_root;
1149 struct backref_cache *cache = &rc->backref_cache;
1150 struct backref_node *node = NULL;
1151 struct backref_node *new_node;
1152 struct backref_edge *edge;
1153 struct backref_edge *new_edge;
1154 struct rb_node *rb_node;
1155
1156 if (cache->last_trans > 0)
1157 update_backref_cache(trans, cache);
1158
1159 rb_node = tree_search(&cache->rb_root, src->commit_root->start);
1160 if (rb_node) {
1161 node = rb_entry(rb_node, struct backref_node, rb_node);
1162 if (node->detached)
1163 node = NULL;
1164 else
1165 BUG_ON(node->new_bytenr != reloc_root->node->start);
1166 }
1167
1168 if (!node) {
1169 rb_node = tree_search(&cache->rb_root,
1170 reloc_root->commit_root->start);
1171 if (rb_node) {
1172 node = rb_entry(rb_node, struct backref_node,
1173 rb_node);
1174 BUG_ON(node->detached);
1175 }
1176 }
1177
1178 if (!node)
1179 return 0;
1180
1181 new_node = alloc_backref_node(cache);
1182 if (!new_node)
1183 return -ENOMEM;
1184
1185 new_node->bytenr = dest->node->start;
1186 new_node->level = node->level;
1187 new_node->lowest = node->lowest;
6848ad64 1188 new_node->checked = 1;
3fd0a558
YZ		 1189 new_node->root = dest;
1190
1191 if (!node->lowest) {
1192 list_for_each_entry(edge, &node->lower, list[UPPER]) {
1193 new_edge = alloc_backref_edge(cache);
1194 if (!new_edge)
1195 goto fail;
1196
1197 new_edge->node[UPPER] = new_node;
1198 new_edge->node[LOWER] = edge->node[LOWER];
1199 list_add_tail(&new_edge->list[UPPER],
1200 &new_node->lower);
1201 }
76b9e23d
MX		 1202 } else {
1203 list_add_tail(&new_node->lower, &cache->leaves);
3fd0a558
YZ		 1204 }
1205
1206 rb_node = tree_insert(&cache->rb_root, new_node->bytenr,
1207 &new_node->rb_node);
43c04fb1
JM		 1208 if (rb_node)
1209 backref_tree_panic(rb_node, -EEXIST, new_node->bytenr);
3fd0a558
YZ		 1210
1211 if (!new_node->lowest) {
1212 list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {
1213 list_add_tail(&new_edge->list[LOWER],
1214 &new_edge->node[LOWER]->upper);
1215 }
1216 }
1217 return 0;
1218fail:
1219 while (!list_empty(&new_node->lower)) {
1220 new_edge = list_entry(new_node->lower.next,
1221 struct backref_edge, list[UPPER]);
1222 list_del(&new_edge->list[UPPER]);
1223 free_backref_edge(cache, new_edge);
1224 }
1225 free_backref_node(cache, new_node);
1226 return -ENOMEM;
1227}
1228
5d4f98a2
YZ		 1229/*
1230 * helper to add 'address of tree root -> reloc tree' mapping
1231 */
ffd7b339 1232static int __must_check __add_reloc_root(struct btrfs_root *root)
5d4f98a2
YZ		 1233{
1234 struct rb_node *rb_node;
1235 struct mapping_node *node;
1236 struct reloc_control *rc = root->fs_info->reloc_ctl;
1237
1238 node = kmalloc(sizeof(*node), GFP_NOFS);
ffd7b339
JM		 1239 if (!node)
1240 return -ENOMEM;
5d4f98a2
YZ		 1241
1242 node->bytenr = root->node->start;
1243 node->data = root;
1244
1245 spin_lock(&rc->reloc_root_tree.lock);
1246 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1247 node->bytenr, &node->rb_node);
1248 spin_unlock(&rc->reloc_root_tree.lock);
ffd7b339 1249 if (rb_node) {
ffd7b339
JM		 1250 btrfs_panic(root->fs_info, -EEXIST, "Duplicate root found "
1251 "for start=%llu while inserting into relocation "
533574c6 1252 "tree\n", node->bytenr);
23291a04
DC		 1253 kfree(node);
1254 return -EEXIST;
ffd7b339 1255 }
5d4f98a2
YZ		 1256
1257 list_add_tail(&root->root_list, &rc->reloc_roots);
1258 return 0;
1259}
1260
1261/*
1262 * helper to update/delete the 'address of tree root -> reloc tree'
1263 * mapping
1264 */
1265static int __update_reloc_root(struct btrfs_root *root, int del)
1266{
1267 struct rb_node *rb_node;
1268 struct mapping_node *node = NULL;
1269 struct reloc_control *rc = root->fs_info->reloc_ctl;
1270
1271 spin_lock(&rc->reloc_root_tree.lock);
1272 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1273 root->commit_root->start);
1274 if (rb_node) {
1275 node = rb_entry(rb_node, struct mapping_node, rb_node);
1276 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1277 }
1278 spin_unlock(&rc->reloc_root_tree.lock);
1279
8f71f3e0
LB		 1280 if (!node)
1281 return 0;
5d4f98a2
YZ		 1282 BUG_ON((struct btrfs_root *)node->data != root);
1283
1284 if (!del) {
1285 spin_lock(&rc->reloc_root_tree.lock);
1286 node->bytenr = root->node->start;
1287 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1288 node->bytenr, &node->rb_node);
1289 spin_unlock(&rc->reloc_root_tree.lock);
43c04fb1
JM		 1290 if (rb_node)
1291 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
5d4f98a2 1292 } else {
1daf3540 1293 spin_lock(&root->fs_info->trans_lock);
5d4f98a2 1294 list_del_init(&root->root_list);
1daf3540 1295 spin_unlock(&root->fs_info->trans_lock);
5d4f98a2
YZ		 1296 kfree(node);
1297 }
1298 return 0;
1299}
1300
3fd0a558
YZ		 1301static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
1302 struct btrfs_root *root, u64 objectid)
5d4f98a2
YZ		 1303{
1304 struct btrfs_root *reloc_root;
1305 struct extent_buffer *eb;
1306 struct btrfs_root_item *root_item;
1307 struct btrfs_key root_key;
1308 int ret;
1309
5d4f98a2
YZ		 1310 root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
1311 BUG_ON(!root_item);
1312
1313 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
1314 root_key.type = BTRFS_ROOT_ITEM_KEY;
3fd0a558 1315 root_key.offset = objectid;
5d4f98a2 1316
3fd0a558
YZ		 1317 if (root->root_key.objectid == objectid) {
1318 /* called by btrfs_init_reloc_root */
1319 ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
1320 BTRFS_TREE_RELOC_OBJECTID);
1321 BUG_ON(ret);
1322
1323 btrfs_set_root_last_snapshot(&root->root_item,
1324 trans->transid - 1);
1325 } else {
1326 /*
1327 * called by btrfs_reloc_post_snapshot_hook.
1328 * the source tree is a reloc tree, all tree blocks
1329 * modified after it was created have RELOC flag
1330 * set in their headers. so it's OK to not update
1331 * the 'last_snapshot'.
1332 */
1333 ret = btrfs_copy_root(trans, root, root->node, &eb,
1334 BTRFS_TREE_RELOC_OBJECTID);
1335 BUG_ON(ret);
1336 }
5d4f98a2 1337
5d4f98a2 1338 memcpy(root_item, &root->root_item, sizeof(*root_item));
5d4f98a2
YZ		 1339 btrfs_set_root_bytenr(root_item, eb->start);
1340 btrfs_set_root_level(root_item, btrfs_header_level(eb));
1341 btrfs_set_root_generation(root_item, trans->transid);
3fd0a558
YZ		 1342
1343 if (root->root_key.objectid == objectid) {
1344 btrfs_set_root_refs(root_item, 0);
1345 memset(&root_item->drop_progress, 0,
1346 sizeof(struct btrfs_disk_key));
1347 root_item->drop_level = 0;
1348 }
5d4f98a2
YZ		 1349
1350 btrfs_tree_unlock(eb);
1351 free_extent_buffer(eb);
1352
1353 ret = btrfs_insert_root(trans, root->fs_info->tree_root,
1354 &root_key, root_item);
1355 BUG_ON(ret);
1356 kfree(root_item);
1357
cb517eab 1358 reloc_root = btrfs_read_fs_root(root->fs_info->tree_root, &root_key);
5d4f98a2
YZ		 1359 BUG_ON(IS_ERR(reloc_root));
1360 reloc_root->last_trans = trans->transid;
3fd0a558
YZ		 1361 return reloc_root;
1362}
1363
1364/*
1365 * create reloc tree for a given fs tree. reloc tree is just a
1366 * snapshot of the fs tree with special root objectid.
1367 */
1368int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
1369 struct btrfs_root *root)
1370{
1371 struct btrfs_root *reloc_root;
1372 struct reloc_control *rc = root->fs_info->reloc_ctl;
1373 int clear_rsv = 0;
ffd7b339 1374 int ret;
3fd0a558
YZ		 1375
1376 if (root->reloc_root) {
1377 reloc_root = root->reloc_root;
1378 reloc_root->last_trans = trans->transid;
1379 return 0;
1380 }
1381
1382 if (!rc || !rc->create_reloc_tree ||
1383 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1384 return 0;
1385
1386 if (!trans->block_rsv) {
1387 trans->block_rsv = rc->block_rsv;
1388 clear_rsv = 1;
1389 }
1390 reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
1391 if (clear_rsv)
1392 trans->block_rsv = NULL;
5d4f98a2 1393
ffd7b339
JM		 1394 ret = __add_reloc_root(reloc_root);
1395 BUG_ON(ret < 0);
5d4f98a2
YZ		 1396 root->reloc_root = reloc_root;
1397 return 0;
1398}
1399
1400/*
1401 * update root item of reloc tree
1402 */
1403int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
1404 struct btrfs_root *root)
1405{
1406 struct btrfs_root *reloc_root;
1407 struct btrfs_root_item *root_item;
1408 int del = 0;
1409 int ret;
1410
1411 if (!root->reloc_root)
7585717f 1412 goto out;
5d4f98a2
YZ		 1413
1414 reloc_root = root->reloc_root;
1415 root_item = &reloc_root->root_item;
1416
3fd0a558
YZ		 1417 if (root->fs_info->reloc_ctl->merge_reloc_tree &&
1418 btrfs_root_refs(root_item) == 0) {
5d4f98a2
YZ		 1419 root->reloc_root = NULL;
1420 del = 1;
1421 }
1422
1423 __update_reloc_root(reloc_root, del);
1424
1425 if (reloc_root->commit_root != reloc_root->node) {
1426 btrfs_set_root_node(root_item, reloc_root->node);
1427 free_extent_buffer(reloc_root->commit_root);
1428 reloc_root->commit_root = btrfs_root_node(reloc_root);
1429 }
1430
1431 ret = btrfs_update_root(trans, root->fs_info->tree_root,
1432 &reloc_root->root_key, root_item);
1433 BUG_ON(ret);
7585717f
CM		 1434
1435out:
5d4f98a2
YZ		 1436 return 0;
1437}
1438
1439/*
1440 * helper to find first cached inode with inode number >= objectid
1441 * in a subvolume
1442 */
1443static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
1444{
1445 struct rb_node *node;
1446 struct rb_node *prev;
1447 struct btrfs_inode *entry;
1448 struct inode *inode;
1449
1450 spin_lock(&root->inode_lock);
1451again:
1452 node = root->inode_tree.rb_node;
1453 prev = NULL;
1454 while (node) {
1455 prev = node;
1456 entry = rb_entry(node, struct btrfs_inode, rb_node);
1457
33345d01 1458 if (objectid < btrfs_ino(&entry->vfs_inode))
5d4f98a2 1459 node = node->rb_left;
33345d01 1460 else if (objectid > btrfs_ino(&entry->vfs_inode))
5d4f98a2
YZ		 1461 node = node->rb_right;
1462 else
1463 break;
1464 }
1465 if (!node) {
1466 while (prev) {
1467 entry = rb_entry(prev, struct btrfs_inode, rb_node);
33345d01 1468 if (objectid <= btrfs_ino(&entry->vfs_inode)) {
5d4f98a2
YZ		 1469 node = prev;
1470 break;
1471 }
1472 prev = rb_next(prev);
1473 }
1474 }
1475 while (node) {
1476 entry = rb_entry(node, struct btrfs_inode, rb_node);
1477 inode = igrab(&entry->vfs_inode);
1478 if (inode) {
1479 spin_unlock(&root->inode_lock);
1480 return inode;
1481 }
1482
33345d01 1483 objectid = btrfs_ino(&entry->vfs_inode) + 1;
5d4f98a2
YZ		 1484 if (cond_resched_lock(&root->inode_lock))
1485 goto again;
1486
1487 node = rb_next(node);
1488 }
1489 spin_unlock(&root->inode_lock);
1490 return NULL;
1491}
1492
1493static int in_block_group(u64 bytenr,
1494 struct btrfs_block_group_cache *block_group)
1495{
1496 if (bytenr >= block_group->key.objectid &&
1497 bytenr < block_group->key.objectid + block_group->key.offset)
1498 return 1;
1499 return 0;
1500}
1501
1502/*
1503 * get new location of data
1504 */
1505static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1506 u64 bytenr, u64 num_bytes)
1507{
1508 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
1509 struct btrfs_path *path;
1510 struct btrfs_file_extent_item *fi;
1511 struct extent_buffer *leaf;
1512 int ret;
1513
1514 path = btrfs_alloc_path();
1515 if (!path)
1516 return -ENOMEM;
1517
1518 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
33345d01 1519 ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(reloc_inode),
5d4f98a2
YZ		 1520 bytenr, 0);
1521 if (ret < 0)
1522 goto out;
1523 if (ret > 0) {
1524 ret = -ENOENT;
1525 goto out;
1526 }
1527
1528 leaf = path->nodes[0];
1529 fi = btrfs_item_ptr(leaf, path->slots[0],
1530 struct btrfs_file_extent_item);
1531
1532 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1533 btrfs_file_extent_compression(leaf, fi) ||
1534 btrfs_file_extent_encryption(leaf, fi) ||
1535 btrfs_file_extent_other_encoding(leaf, fi));
1536
1537 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1538 ret = 1;
1539 goto out;
1540 }
1541
3fd0a558 1542 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
5d4f98a2
YZ		 1543 ret = 0;
1544out:
1545 btrfs_free_path(path);
1546 return ret;
1547}
1548
1549/*
1550 * update file extent items in the tree leaf to point to
1551 * the new locations.
1552 */
3fd0a558
YZ		 1553static noinline_for_stack
1554int replace_file_extents(struct btrfs_trans_handle *trans,
1555 struct reloc_control *rc,
1556 struct btrfs_root *root,
1557 struct extent_buffer *leaf)
5d4f98a2
YZ		 1558{
1559 struct btrfs_key key;
1560 struct btrfs_file_extent_item *fi;
1561 struct inode *inode = NULL;
5d4f98a2
YZ		 1562 u64 parent;
1563 u64 bytenr;
3fd0a558 1564 u64 new_bytenr = 0;
5d4f98a2
YZ		 1565 u64 num_bytes;
1566 u64 end;
1567 u32 nritems;
1568 u32 i;
1569 int ret;
1570 int first = 1;
1571 int dirty = 0;
1572
1573 if (rc->stage != UPDATE_DATA_PTRS)
1574 return 0;
1575
1576 /* reloc trees always use full backref */
1577 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1578 parent = leaf->start;
1579 else
1580 parent = 0;
1581
1582 nritems = btrfs_header_nritems(leaf);
1583 for (i = 0; i < nritems; i++) {
1584 cond_resched();
1585 btrfs_item_key_to_cpu(leaf, &key, i);
1586 if (key.type != BTRFS_EXTENT_DATA_KEY)
1587 continue;
1588 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1589 if (btrfs_file_extent_type(leaf, fi) ==
1590 BTRFS_FILE_EXTENT_INLINE)
1591 continue;
1592 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1593 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1594 if (bytenr == 0)
1595 continue;
1596 if (!in_block_group(bytenr, rc->block_group))
1597 continue;
1598
1599 /*
1600 * if we are modifying block in fs tree, wait for readpage
1601 * to complete and drop the extent cache
1602 */
1603 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
5d4f98a2
YZ		 1604 if (first) {
1605 inode = find_next_inode(root, key.objectid);
5d4f98a2 1606 first = 0;
33345d01 1607 } else if (inode && btrfs_ino(inode) < key.objectid) {
3fd0a558 1608 btrfs_add_delayed_iput(inode);
5d4f98a2 1609 inode = find_next_inode(root, key.objectid);
5d4f98a2 1610 }
33345d01 1611 if (inode && btrfs_ino(inode) == key.objectid) {
5d4f98a2
YZ		 1612 end = key.offset +
1613 btrfs_file_extent_num_bytes(leaf, fi);
1614 WARN_ON(!IS_ALIGNED(key.offset,
1615 root->sectorsize));
1616 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
1617 end--;
1618 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
d0082371 1619 key.offset, end);
5d4f98a2
YZ		 1620 if (!ret)
1621 continue;
1622
1623 btrfs_drop_extent_cache(inode, key.offset, end,
1624 1);
1625 unlock_extent(&BTRFS_I(inode)->io_tree,
d0082371 1626 key.offset, end);
5d4f98a2
YZ		 1627 }
1628 }
1629
1630 ret = get_new_location(rc->data_inode, &new_bytenr,
1631 bytenr, num_bytes);
3fd0a558
YZ		 1632 if (ret > 0) {
1633 WARN_ON(1);
5d4f98a2 1634 continue;
3fd0a558 1635 }
5d4f98a2
YZ		 1636 BUG_ON(ret < 0);
1637
1638 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1639 dirty = 1;
1640
1641 key.offset -= btrfs_file_extent_offset(leaf, fi);
1642 ret = btrfs_inc_extent_ref(trans, root, new_bytenr,
1643 num_bytes, parent,
1644 btrfs_header_owner(leaf),
66d7e7f0 1645 key.objectid, key.offset, 1);
5d4f98a2
YZ		 1646 BUG_ON(ret);
1647
1648 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1649 parent, btrfs_header_owner(leaf),
66d7e7f0 1650 key.objectid, key.offset, 1);
5d4f98a2
YZ		 1651 BUG_ON(ret);
1652 }
1653 if (dirty)
1654 btrfs_mark_buffer_dirty(leaf);
3fd0a558
YZ		 1655 if (inode)
1656 btrfs_add_delayed_iput(inode);
5d4f98a2
YZ		 1657 return 0;
1658}
1659
1660static noinline_for_stack
1661int memcmp_node_keys(struct extent_buffer *eb, int slot,
1662 struct btrfs_path *path, int level)
1663{
1664 struct btrfs_disk_key key1;
1665 struct btrfs_disk_key key2;
1666 btrfs_node_key(eb, &key1, slot);
1667 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1668 return memcmp(&key1, &key2, sizeof(key1));
1669}
1670
1671/*
1672 * try to replace tree blocks in fs tree with the new blocks
1673 * in reloc tree. tree blocks haven't been modified since the
1674 * reloc tree was create can be replaced.
1675 *
1676 * if a block was replaced, level of the block + 1 is returned.
1677 * if no block got replaced, 0 is returned. if there are other
1678 * errors, a negative error number is returned.
1679 */
3fd0a558
YZ		 1680static noinline_for_stack
1681int replace_path(struct btrfs_trans_handle *trans,
1682 struct btrfs_root *dest, struct btrfs_root *src,
1683 struct btrfs_path *path, struct btrfs_key *next_key,
1684 int lowest_level, int max_level)
5d4f98a2
YZ		 1685{
1686 struct extent_buffer *eb;
1687 struct extent_buffer *parent;
1688 struct btrfs_key key;
1689 u64 old_bytenr;
1690 u64 new_bytenr;
1691 u64 old_ptr_gen;
1692 u64 new_ptr_gen;
1693 u64 last_snapshot;
1694 u32 blocksize;
3fd0a558 1695 int cow = 0;
5d4f98a2
YZ		 1696 int level;
1697 int ret;
1698 int slot;
1699
1700 BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1701 BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
5d4f98a2
YZ		 1702
1703 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
3fd0a558 1704again:
5d4f98a2
YZ		 1705 slot = path->slots[lowest_level];
1706 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1707
1708 eb = btrfs_lock_root_node(dest);
1709 btrfs_set_lock_blocking(eb);
1710 level = btrfs_header_level(eb);
1711
1712 if (level < lowest_level) {
1713 btrfs_tree_unlock(eb);
1714 free_extent_buffer(eb);
1715 return 0;
1716 }
1717
3fd0a558
YZ		 1718 if (cow) {
1719 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
1720 BUG_ON(ret);
1721 }
5d4f98a2
YZ		 1722 btrfs_set_lock_blocking(eb);
1723
1724 if (next_key) {
1725 next_key->objectid = (u64)-1;
1726 next_key->type = (u8)-1;
1727 next_key->offset = (u64)-1;
1728 }
1729
1730 parent = eb;
1731 while (1) {
1732 level = btrfs_header_level(parent);
1733 BUG_ON(level < lowest_level);
1734
1735 ret = btrfs_bin_search(parent, &key, level, &slot);
1736 if (ret && slot > 0)
1737 slot--;
1738
1739 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1740 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1741
1742 old_bytenr = btrfs_node_blockptr(parent, slot);
1743 blocksize = btrfs_level_size(dest, level - 1);
1744 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1745
1746 if (level <= max_level) {
1747 eb = path->nodes[level];
1748 new_bytenr = btrfs_node_blockptr(eb,
1749 path->slots[level]);
1750 new_ptr_gen = btrfs_node_ptr_generation(eb,
1751 path->slots[level]);
1752 } else {
1753 new_bytenr = 0;
1754 new_ptr_gen = 0;
1755 }
1756
1757 if (new_bytenr > 0 && new_bytenr == old_bytenr) {
1758 WARN_ON(1);
1759 ret = level;
1760 break;
1761 }
1762
1763 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1764 memcmp_node_keys(parent, slot, path, level)) {
3fd0a558 1765 if (level <= lowest_level) {
5d4f98a2
YZ		 1766 ret = 0;
1767 break;
1768 }
1769
1770 eb = read_tree_block(dest, old_bytenr, blocksize,
1771 old_ptr_gen);
416bc658
JB		 1772 if (!eb || !extent_buffer_uptodate(eb)) {
1773 ret = (!eb) ? -ENOMEM : -EIO;
1774 free_extent_buffer(eb);
379cde74 1775 break;
416bc658 1776 }
5d4f98a2 1777 btrfs_tree_lock(eb);
3fd0a558
YZ		 1778 if (cow) {
1779 ret = btrfs_cow_block(trans, dest, eb, parent,
1780 slot, &eb);
1781 BUG_ON(ret);
5d4f98a2 1782 }
3fd0a558 1783 btrfs_set_lock_blocking(eb);
5d4f98a2
YZ		 1784
1785 btrfs_tree_unlock(parent);
1786 free_extent_buffer(parent);
1787
1788 parent = eb;
1789 continue;
1790 }
1791
3fd0a558
YZ		 1792 if (!cow) {
1793 btrfs_tree_unlock(parent);
1794 free_extent_buffer(parent);
1795 cow = 1;
1796 goto again;
1797 }
1798
5d4f98a2
YZ		 1799 btrfs_node_key_to_cpu(path->nodes[level], &key,
1800 path->slots[level]);
b3b4aa74 1801 btrfs_release_path(path);
5d4f98a2
YZ		 1802
1803 path->lowest_level = level;
1804 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1805 path->lowest_level = 0;
1806 BUG_ON(ret);
1807
1808 /*
1809 * swap blocks in fs tree and reloc tree.
1810 */
1811 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1812 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1813 btrfs_mark_buffer_dirty(parent);
1814
1815 btrfs_set_node_blockptr(path->nodes[level],
1816 path->slots[level], old_bytenr);
1817 btrfs_set_node_ptr_generation(path->nodes[level],
1818 path->slots[level], old_ptr_gen);
1819 btrfs_mark_buffer_dirty(path->nodes[level]);
1820
1821 ret = btrfs_inc_extent_ref(trans, src, old_bytenr, blocksize,
1822 path->nodes[level]->start,
66d7e7f0
AJ		 1823 src->root_key.objectid, level - 1, 0,
1824 1);
5d4f98a2
YZ		 1825 BUG_ON(ret);
1826 ret = btrfs_inc_extent_ref(trans, dest, new_bytenr, blocksize,
1827 0, dest->root_key.objectid, level - 1,
66d7e7f0 1828 0, 1);
5d4f98a2
YZ		 1829 BUG_ON(ret);
1830
1831 ret = btrfs_free_extent(trans, src, new_bytenr, blocksize,
1832 path->nodes[level]->start,
66d7e7f0
AJ		 1833 src->root_key.objectid, level - 1, 0,
1834 1);
5d4f98a2
YZ		 1835 BUG_ON(ret);
1836
1837 ret = btrfs_free_extent(trans, dest, old_bytenr, blocksize,
1838 0, dest->root_key.objectid, level - 1,
66d7e7f0 1839 0, 1);
5d4f98a2
YZ		 1840 BUG_ON(ret);
1841
1842 btrfs_unlock_up_safe(path, 0);
1843
1844 ret = level;
1845 break;
1846 }
1847 btrfs_tree_unlock(parent);
1848 free_extent_buffer(parent);
1849 return ret;
1850}
1851
1852/*
1853 * helper to find next relocated block in reloc tree
1854 */
1855static noinline_for_stack
1856int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1857 int *level)
1858{
1859 struct extent_buffer *eb;
1860 int i;
1861 u64 last_snapshot;
1862 u32 nritems;
1863
1864 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1865
1866 for (i = 0; i < *level; i++) {
1867 free_extent_buffer(path->nodes[i]);
1868 path->nodes[i] = NULL;
1869 }
1870
1871 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
1872 eb = path->nodes[i];
1873 nritems = btrfs_header_nritems(eb);
1874 while (path->slots[i] + 1 < nritems) {
1875 path->slots[i]++;
1876 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
1877 last_snapshot)
1878 continue;
1879
1880 *level = i;
1881 return 0;
1882 }
1883 free_extent_buffer(path->nodes[i]);
1884 path->nodes[i] = NULL;
1885 }
1886 return 1;
1887}
1888
1889/*
1890 * walk down reloc tree to find relocated block of lowest level
1891 */
1892static noinline_for_stack
1893int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1894 int *level)
1895{
1896 struct extent_buffer *eb = NULL;
1897 int i;
1898 u64 bytenr;
1899 u64 ptr_gen = 0;
1900 u64 last_snapshot;
1901 u32 blocksize;
1902 u32 nritems;
1903
1904 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1905
1906 for (i = *level; i > 0; i--) {
1907 eb = path->nodes[i];
1908 nritems = btrfs_header_nritems(eb);
1909 while (path->slots[i] < nritems) {
1910 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
1911 if (ptr_gen > last_snapshot)
1912 break;
1913 path->slots[i]++;
1914 }
1915 if (path->slots[i] >= nritems) {
1916 if (i == *level)
1917 break;
1918 *level = i + 1;
1919 return 0;
1920 }
1921 if (i == 1) {
1922 *level = i;
1923 return 0;
1924 }
1925
1926 bytenr = btrfs_node_blockptr(eb, path->slots[i]);
1927 blocksize = btrfs_level_size(root, i - 1);
1928 eb = read_tree_block(root, bytenr, blocksize, ptr_gen);
416bc658
JB		 1929 if (!eb || !extent_buffer_uptodate(eb)) {
1930 free_extent_buffer(eb);
1931 return -EIO;
1932 }
5d4f98a2
YZ		 1933 BUG_ON(btrfs_header_level(eb) != i - 1);
1934 path->nodes[i - 1] = eb;
1935 path->slots[i - 1] = 0;
1936 }
1937 return 1;
1938}
1939
1940/*
1941 * invalidate extent cache for file extents whose key in range of
1942 * [min_key, max_key)
1943 */
1944static int invalidate_extent_cache(struct btrfs_root *root,
1945 struct btrfs_key *min_key,
1946 struct btrfs_key *max_key)
1947{
1948 struct inode *inode = NULL;
1949 u64 objectid;
1950 u64 start, end;
33345d01 1951 u64 ino;
5d4f98a2
YZ		 1952
1953 objectid = min_key->objectid;
1954 while (1) {
1955 cond_resched();
1956 iput(inode);
1957
1958 if (objectid > max_key->objectid)
1959 break;
1960
1961 inode = find_next_inode(root, objectid);
1962 if (!inode)
1963 break;
33345d01 1964 ino = btrfs_ino(inode);
5d4f98a2 1965
33345d01 1966 if (ino > max_key->objectid) {
5d4f98a2
YZ		 1967 iput(inode);
1968 break;
1969 }
1970
33345d01 1971 objectid = ino + 1;
5d4f98a2
YZ		 1972 if (!S_ISREG(inode->i_mode))
1973 continue;
1974
33345d01 1975 if (unlikely(min_key->objectid == ino)) {
5d4f98a2
YZ		 1976 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
1977 continue;
1978 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
1979 start = 0;
1980 else {
1981 start = min_key->offset;
1982 WARN_ON(!IS_ALIGNED(start, root->sectorsize));
1983 }
1984 } else {
1985 start = 0;
1986 }
1987
33345d01 1988 if (unlikely(max_key->objectid == ino)) {
5d4f98a2
YZ		 1989 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
1990 continue;
1991 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
1992 end = (u64)-1;
1993 } else {
1994 if (max_key->offset == 0)
1995 continue;
1996 end = max_key->offset;
1997 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
1998 end--;
1999 }
2000 } else {
2001 end = (u64)-1;
2002 }
2003
2004 /* the lock_extent waits for readpage to complete */
d0082371 2005 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
5d4f98a2 2006 btrfs_drop_extent_cache(inode, start, end, 1);
d0082371 2007 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
5d4f98a2
YZ		 2008 }
2009 return 0;
2010}
2011
2012static int find_next_key(struct btrfs_path *path, int level,
2013 struct btrfs_key *key)
2014
2015{
2016 while (level < BTRFS_MAX_LEVEL) {
2017 if (!path->nodes[level])
2018 break;
2019 if (path->slots[level] + 1 <
2020 btrfs_header_nritems(path->nodes[level])) {
2021 btrfs_node_key_to_cpu(path->nodes[level], key,
2022 path->slots[level] + 1);
2023 return 0;
2024 }
2025 level++;
2026 }
2027 return 1;
2028}
2029
2030/*
2031 * merge the relocated tree blocks in reloc tree with corresponding
2032 * fs tree.
2033 */
2034static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
2035 struct btrfs_root *root)
2036{
2037 LIST_HEAD(inode_list);
2038 struct btrfs_key key;
2039 struct btrfs_key next_key;
2040 struct btrfs_trans_handle *trans;
2041 struct btrfs_root *reloc_root;
2042 struct btrfs_root_item *root_item;
2043 struct btrfs_path *path;
3fd0a558 2044 struct extent_buffer *leaf;
5d4f98a2
YZ		 2045 int level;
2046 int max_level;
2047 int replaced = 0;
2048 int ret;
2049 int err = 0;
3fd0a558 2050 u32 min_reserved;
5d4f98a2
YZ		 2051
2052 path = btrfs_alloc_path();
2053 if (!path)
2054 return -ENOMEM;
026fd317 2055 path->reada = 1;
5d4f98a2
YZ		 2056
2057 reloc_root = root->reloc_root;
2058 root_item = &reloc_root->root_item;
2059
2060 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2061 level = btrfs_root_level(root_item);
2062 extent_buffer_get(reloc_root->node);
2063 path->nodes[level] = reloc_root->node;
2064 path->slots[level] = 0;
2065 } else {
2066 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2067
2068 level = root_item->drop_level;
2069 BUG_ON(level == 0);
2070 path->lowest_level = level;
2071 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
33c66f43 2072 path->lowest_level = 0;
5d4f98a2
YZ		 2073 if (ret < 0) {
2074 btrfs_free_path(path);
2075 return ret;
2076 }
2077
2078 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
2079 path->slots[level]);
2080 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
2081
2082 btrfs_unlock_up_safe(path, 0);
2083 }
2084
3fd0a558
YZ		 2085 min_reserved = root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2086 memset(&next_key, 0, sizeof(next_key));
5d4f98a2 2087
3fd0a558
YZ		 2088 while (1) {
2089 trans = btrfs_start_transaction(root, 0);
98d5dc13 2090 BUG_ON(IS_ERR(trans));
3fd0a558 2091 trans->block_rsv = rc->block_rsv;
5d4f98a2 2092
08e007d2
MX		 2093 ret = btrfs_block_rsv_refill(root, rc->block_rsv, min_reserved,
2094 BTRFS_RESERVE_FLUSH_ALL);
3fd0a558
YZ		 2095 if (ret) {
2096 BUG_ON(ret != -EAGAIN);
2097 ret = btrfs_commit_transaction(trans, root);
2098 BUG_ON(ret);
2099 continue;
5d4f98a2
YZ		 2100 }
2101
5d4f98a2 2102 replaced = 0;
5d4f98a2
YZ		 2103 max_level = level;
2104
2105 ret = walk_down_reloc_tree(reloc_root, path, &level);
2106 if (ret < 0) {
2107 err = ret;
2108 goto out;
2109 }
2110 if (ret > 0)
2111 break;
2112
2113 if (!find_next_key(path, level, &key) &&
2114 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
2115 ret = 0;
5d4f98a2 2116 } else {
3fd0a558
YZ		 2117 ret = replace_path(trans, root, reloc_root, path,
2118 &next_key, level, max_level);
5d4f98a2
YZ		 2119 }
2120 if (ret < 0) {
2121 err = ret;
2122 goto out;
2123 }
2124
2125 if (ret > 0) {
2126 level = ret;
2127 btrfs_node_key_to_cpu(path->nodes[level], &key,
2128 path->slots[level]);
2129 replaced = 1;
5d4f98a2
YZ		 2130 }
2131
2132 ret = walk_up_reloc_tree(reloc_root, path, &level);
2133 if (ret > 0)
2134 break;
2135
2136 BUG_ON(level == 0);
2137 /*
2138 * save the merging progress in the drop_progress.
2139 * this is OK since root refs == 1 in this case.
2140 */
2141 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
2142 path->slots[level]);
2143 root_item->drop_level = level;
2144
3fd0a558 2145 btrfs_end_transaction_throttle(trans, root);
5d4f98a2 2146
b53d3f5d 2147 btrfs_btree_balance_dirty(root);
5d4f98a2
YZ		 2148
2149 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2150 invalidate_extent_cache(root, &key, &next_key);
2151 }
2152
2153 /*
2154 * handle the case only one block in the fs tree need to be
2155 * relocated and the block is tree root.
2156 */
2157 leaf = btrfs_lock_root_node(root);
2158 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf);
2159 btrfs_tree_unlock(leaf);
2160 free_extent_buffer(leaf);
2161 if (ret < 0)
2162 err = ret;
2163out:
2164 btrfs_free_path(path);
2165
2166 if (err == 0) {
2167 memset(&root_item->drop_progress, 0,
2168 sizeof(root_item->drop_progress));
2169 root_item->drop_level = 0;
2170 btrfs_set_root_refs(root_item, 0);
3fd0a558 2171 btrfs_update_reloc_root(trans, root);
5d4f98a2
YZ		 2172 }
2173
3fd0a558 2174 btrfs_end_transaction_throttle(trans, root);
5d4f98a2 2175
b53d3f5d 2176 btrfs_btree_balance_dirty(root);
5d4f98a2 2177
5d4f98a2
YZ		 2178 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2179 invalidate_extent_cache(root, &key, &next_key);
2180
2181 return err;
2182}
2183
3fd0a558
YZ		 2184static noinline_for_stack
2185int prepare_to_merge(struct reloc_control *rc, int err)
5d4f98a2 2186{
3fd0a558 2187 struct btrfs_root *root = rc->extent_root;
5d4f98a2 2188 struct btrfs_root *reloc_root;
3fd0a558
YZ		 2189 struct btrfs_trans_handle *trans;
2190 LIST_HEAD(reloc_roots);
2191 u64 num_bytes = 0;
2192 int ret;
3fd0a558 2193
7585717f 2194 mutex_lock(&root->fs_info->reloc_mutex);
3fd0a558
YZ		 2195 rc->merging_rsv_size += root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2196 rc->merging_rsv_size += rc->nodes_relocated * 2;
7585717f
CM		 2197 mutex_unlock(&root->fs_info->reloc_mutex);
2198
3fd0a558
YZ		 2199again:
2200 if (!err) {
2201 num_bytes = rc->merging_rsv_size;
08e007d2
MX		 2202 ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes,
2203 BTRFS_RESERVE_FLUSH_ALL);
3fd0a558
YZ		 2204 if (ret)
2205 err = ret;
2206 }
2207
7a7eaa40 2208 trans = btrfs_join_transaction(rc->extent_root);
3612b495
TI		 2209 if (IS_ERR(trans)) {
2210 if (!err)
2211 btrfs_block_rsv_release(rc->extent_root,
2212 rc->block_rsv, num_bytes);
2213 return PTR_ERR(trans);
2214 }
3fd0a558
YZ		 2215
2216 if (!err) {
2217 if (num_bytes != rc->merging_rsv_size) {
2218 btrfs_end_transaction(trans, rc->extent_root);
2219 btrfs_block_rsv_release(rc->extent_root,
2220 rc->block_rsv, num_bytes);
3fd0a558
YZ		 2221 goto again;
2222 }
2223 }
5d4f98a2 2224
3fd0a558
YZ		 2225 rc->merge_reloc_tree = 1;
2226
2227 while (!list_empty(&rc->reloc_roots)) {
2228 reloc_root = list_entry(rc->reloc_roots.next,
2229 struct btrfs_root, root_list);
2230 list_del_init(&reloc_root->root_list);
5d4f98a2 2231
5d4f98a2
YZ		 2232 root = read_fs_root(reloc_root->fs_info,
2233 reloc_root->root_key.offset);
2234 BUG_ON(IS_ERR(root));
2235 BUG_ON(root->reloc_root != reloc_root);
2236
3fd0a558
YZ		 2237 /*
2238 * set reference count to 1, so btrfs_recover_relocation
2239 * knows it should resumes merging
2240 */
2241 if (!err)
2242 btrfs_set_root_refs(&reloc_root->root_item, 1);
5d4f98a2 2243 btrfs_update_reloc_root(trans, root);
5d4f98a2 2244
3fd0a558
YZ		 2245 list_add(&reloc_root->root_list, &reloc_roots);
2246 }
5d4f98a2 2247
3fd0a558 2248 list_splice(&reloc_roots, &rc->reloc_roots);
5d4f98a2 2249
3fd0a558
YZ		 2250 if (!err)
2251 btrfs_commit_transaction(trans, rc->extent_root);
2252 else
2253 btrfs_end_transaction(trans, rc->extent_root);
2254 return err;
5d4f98a2
YZ		 2255}
2256
aca1bba6
LB		 2257static noinline_for_stack
2258void free_reloc_roots(struct list_head *list)
2259{
2260 struct btrfs_root *reloc_root;
2261
2262 while (!list_empty(list)) {
2263 reloc_root = list_entry(list->next, struct btrfs_root,
2264 root_list);
2265 __update_reloc_root(reloc_root, 1);
2266 free_extent_buffer(reloc_root->node);
2267 free_extent_buffer(reloc_root->commit_root);
2268 kfree(reloc_root);
2269 }
2270}
2271
3fd0a558
YZ		 2272static noinline_for_stack
2273int merge_reloc_roots(struct reloc_control *rc)
5d4f98a2 2274{
5d4f98a2 2275 struct btrfs_root *root;
3fd0a558
YZ		 2276 struct btrfs_root *reloc_root;
2277 LIST_HEAD(reloc_roots);
2278 int found = 0;
aca1bba6 2279 int ret = 0;
3fd0a558
YZ		 2280again:
2281 root = rc->extent_root;
7585717f
CM		 2282
2283 /*
2284 * this serializes us with btrfs_record_root_in_transaction,
2285 * we have to make sure nobody is in the middle of
2286 * adding their roots to the list while we are
2287 * doing this splice
2288 */
2289 mutex_lock(&root->fs_info->reloc_mutex);
3fd0a558 2290 list_splice_init(&rc->reloc_roots, &reloc_roots);
7585717f 2291 mutex_unlock(&root->fs_info->reloc_mutex);
5d4f98a2 2292
3fd0a558
YZ		 2293 while (!list_empty(&reloc_roots)) {
2294 found = 1;
2295 reloc_root = list_entry(reloc_roots.next,
2296 struct btrfs_root, root_list);
5d4f98a2 2297
3fd0a558
YZ		 2298 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
2299 root = read_fs_root(reloc_root->fs_info,
2300 reloc_root->root_key.offset);
2301 BUG_ON(IS_ERR(root));
2302 BUG_ON(root->reloc_root != reloc_root);
5d4f98a2 2303
3fd0a558 2304 ret = merge_reloc_root(rc, root);
aca1bba6
LB		 2305 if (ret)
2306 goto out;
3fd0a558
YZ		 2307 } else {
2308 list_del_init(&reloc_root->root_list);
2309 }
2c536799 2310 ret = btrfs_drop_snapshot(reloc_root, rc->block_rsv, 0, 1);
aca1bba6
LB		 2311 if (ret < 0) {
2312 if (list_empty(&reloc_root->root_list))
2313 list_add_tail(&reloc_root->root_list,
2314 &reloc_roots);
2315 goto out;
2316 }
5d4f98a2
YZ		 2317 }
2318
3fd0a558
YZ		 2319 if (found) {
2320 found = 0;
2321 goto again;
2322 }
aca1bba6
LB		 2323out:
2324 if (ret) {
2325 btrfs_std_error(root->fs_info, ret);
2326 if (!list_empty(&reloc_roots))
2327 free_reloc_roots(&reloc_roots);
2328 }
2329
5d4f98a2 2330 BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
aca1bba6 2331 return ret;
5d4f98a2
YZ		 2332}
2333
2334static void free_block_list(struct rb_root *blocks)
2335{
2336 struct tree_block *block;
2337 struct rb_node *rb_node;
2338 while ((rb_node = rb_first(blocks))) {
2339 block = rb_entry(rb_node, struct tree_block, rb_node);
2340 rb_erase(rb_node, blocks);
2341 kfree(block);
2342 }
2343}
2344
2345static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
2346 struct btrfs_root *reloc_root)
2347{
2348 struct btrfs_root *root;
2349
2350 if (reloc_root->last_trans == trans->transid)
2351 return 0;
2352
2353 root = read_fs_root(reloc_root->fs_info, reloc_root->root_key.offset);
2354 BUG_ON(IS_ERR(root));
2355 BUG_ON(root->reloc_root != reloc_root);
2356
2357 return btrfs_record_root_in_trans(trans, root);
2358}
2359
3fd0a558
YZ		 2360static noinline_for_stack
2361struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
2362 struct reloc_control *rc,
2363 struct backref_node *node,
2364 struct backref_edge *edges[], int *nr)
5d4f98a2
YZ		 2365{
2366 struct backref_node *next;
2367 struct btrfs_root *root;
3fd0a558
YZ		 2368 int index = 0;
2369
5d4f98a2
YZ		 2370 next = node;
2371 while (1) {
2372 cond_resched();
2373 next = walk_up_backref(next, edges, &index);
2374 root = next->root;
3fd0a558
YZ		 2375 BUG_ON(!root);
2376 BUG_ON(!root->ref_cows);
5d4f98a2
YZ		 2377
2378 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2379 record_reloc_root_in_trans(trans, root);
2380 break;
2381 }
2382
3fd0a558
YZ		 2383 btrfs_record_root_in_trans(trans, root);
2384 root = root->reloc_root;
2385
2386 if (next->new_bytenr != root->node->start) {
2387 BUG_ON(next->new_bytenr);
2388 BUG_ON(!list_empty(&next->list));
2389 next->new_bytenr = root->node->start;
2390 next->root = root;
2391 list_add_tail(&next->list,
2392 &rc->backref_cache.changed);
2393 __mark_block_processed(rc, next);
5d4f98a2
YZ		 2394 break;
2395 }
2396
3fd0a558 2397 WARN_ON(1);
5d4f98a2
YZ		 2398 root = NULL;
2399 next = walk_down_backref(edges, &index);
2400 if (!next || next->level <= node->level)
2401 break;
2402 }
3fd0a558
YZ		 2403 if (!root)
2404 return NULL;
5d4f98a2 2405
3fd0a558
YZ		 2406 *nr = index;
2407 next = node;
2408 /* setup backref node path for btrfs_reloc_cow_block */
2409 while (1) {
2410 rc->backref_cache.path[next->level] = next;
2411 if (--index < 0)
2412 break;
2413 next = edges[index]->node[UPPER];
5d4f98a2 2414 }
5d4f98a2
YZ		 2415 return root;
2416}
2417
3fd0a558
YZ		 2418/*
2419 * select a tree root for relocation. return NULL if the block
2420 * is reference counted. we should use do_relocation() in this
2421 * case. return a tree root pointer if the block isn't reference
2422 * counted. return -ENOENT if the block is root of reloc tree.
2423 */
5d4f98a2
YZ		 2424static noinline_for_stack
2425struct btrfs_root *select_one_root(struct btrfs_trans_handle *trans,
2426 struct backref_node *node)
2427{
3fd0a558
YZ		 2428 struct backref_node *next;
2429 struct btrfs_root *root;
2430 struct btrfs_root *fs_root = NULL;
5d4f98a2 2431 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
3fd0a558
YZ		 2432 int index = 0;
2433
2434 next = node;
2435 while (1) {
2436 cond_resched();
2437 next = walk_up_backref(next, edges, &index);
2438 root = next->root;
2439 BUG_ON(!root);
2440
25985edc 2441 /* no other choice for non-references counted tree */
3fd0a558
YZ		 2442 if (!root->ref_cows)
2443 return root;
2444
2445 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
2446 fs_root = root;
2447
2448 if (next != node)
2449 return NULL;
2450
2451 next = walk_down_backref(edges, &index);
2452 if (!next || next->level <= node->level)
2453 break;
2454 }
2455
2456 if (!fs_root)
2457 return ERR_PTR(-ENOENT);
2458 return fs_root;
5d4f98a2
YZ		 2459}
2460
2461static noinline_for_stack
3fd0a558
YZ		 2462u64 calcu_metadata_size(struct reloc_control *rc,
2463 struct backref_node *node, int reserve)
5d4f98a2 2464{
3fd0a558
YZ		 2465 struct backref_node *next = node;
2466 struct backref_edge *edge;
2467 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2468 u64 num_bytes = 0;
2469 int index = 0;
2470
2471 BUG_ON(reserve && node->processed);
2472
2473 while (next) {
2474 cond_resched();
2475 while (1) {
2476 if (next->processed && (reserve || next != node))
2477 break;
2478
2479 num_bytes += btrfs_level_size(rc->extent_root,
2480 next->level);
2481
2482 if (list_empty(&next->upper))
2483 break;
2484
2485 edge = list_entry(next->upper.next,
2486 struct backref_edge, list[LOWER]);
2487 edges[index++] = edge;
2488 next = edge->node[UPPER];
2489 }
2490 next = walk_down_backref(edges, &index);
2491 }
2492 return num_bytes;
5d4f98a2
YZ		 2493}
2494
3fd0a558
YZ		 2495static int reserve_metadata_space(struct btrfs_trans_handle *trans,
2496 struct reloc_control *rc,
2497 struct backref_node *node)
5d4f98a2 2498{
3fd0a558
YZ		 2499 struct btrfs_root *root = rc->extent_root;
2500 u64 num_bytes;
2501 int ret;
2502
2503 num_bytes = calcu_metadata_size(rc, node, 1) * 2;
5d4f98a2 2504
3fd0a558 2505 trans->block_rsv = rc->block_rsv;
08e007d2
MX		 2506 ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes,
2507 BTRFS_RESERVE_FLUSH_ALL);
3fd0a558
YZ		 2508 if (ret) {
2509 if (ret == -EAGAIN)
2510 rc->commit_transaction = 1;
2511 return ret;
5d4f98a2 2512 }
3fd0a558 2513
3fd0a558
YZ		 2514 return 0;
2515}
2516
2517static void release_metadata_space(struct reloc_control *rc,
2518 struct backref_node *node)
2519{
2520 u64 num_bytes = calcu_metadata_size(rc, node, 0) * 2;
2521 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, num_bytes);
5d4f98a2
YZ		 2522}
2523
2524/*
2525 * relocate a block tree, and then update pointers in upper level
2526 * blocks that reference the block to point to the new location.
2527 *
2528 * if called by link_to_upper, the block has already been relocated.
2529 * in that case this function just updates pointers.
2530 */
2531static int do_relocation(struct btrfs_trans_handle *trans,
3fd0a558 2532 struct reloc_control *rc,
5d4f98a2
YZ		 2533 struct backref_node *node,
2534 struct btrfs_key *key,
2535 struct btrfs_path *path, int lowest)
2536{
2537 struct backref_node *upper;
2538 struct backref_edge *edge;
2539 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2540 struct btrfs_root *root;
2541 struct extent_buffer *eb;
2542 u32 blocksize;
2543 u64 bytenr;
2544 u64 generation;
2545 int nr;
2546 int slot;
2547 int ret;
2548 int err = 0;
2549
2550 BUG_ON(lowest && node->eb);
2551
2552 path->lowest_level = node->level + 1;
3fd0a558 2553 rc->backref_cache.path[node->level] = node;
5d4f98a2
YZ		 2554 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2555 cond_resched();
5d4f98a2
YZ		 2556
2557 upper = edge->node[UPPER];
3fd0a558
YZ		 2558 root = select_reloc_root(trans, rc, upper, edges, &nr);
2559 BUG_ON(!root);
2560
2561 if (upper->eb && !upper->locked) {
2562 if (!lowest) {
2563 ret = btrfs_bin_search(upper->eb, key,
2564 upper->level, &slot);
2565 BUG_ON(ret);
2566 bytenr = btrfs_node_blockptr(upper->eb, slot);
2567 if (node->eb->start == bytenr)
2568 goto next;
2569 }
5d4f98a2 2570 drop_node_buffer(upper);
3fd0a558 2571 }
5d4f98a2
YZ		 2572
2573 if (!upper->eb) {
2574 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2575 if (ret < 0) {
2576 err = ret;
2577 break;
2578 }
2579 BUG_ON(ret > 0);
2580
3fd0a558
YZ		 2581 if (!upper->eb) {
2582 upper->eb = path->nodes[upper->level];
2583 path->nodes[upper->level] = NULL;
2584 } else {
2585 BUG_ON(upper->eb != path->nodes[upper->level]);
2586 }
5d4f98a2 2587
3fd0a558
YZ		 2588 upper->locked = 1;
2589 path->locks[upper->level] = 0;
5d4f98a2 2590
3fd0a558 2591 slot = path->slots[upper->level];
b3b4aa74 2592 btrfs_release_path(path);
5d4f98a2
YZ		 2593 } else {
2594 ret = btrfs_bin_search(upper->eb, key, upper->level,
2595 &slot);
2596 BUG_ON(ret);
2597 }
2598
2599 bytenr = btrfs_node_blockptr(upper->eb, slot);
3fd0a558
YZ		 2600 if (lowest) {
2601 BUG_ON(bytenr != node->bytenr);
5d4f98a2 2602 } else {
3fd0a558
YZ		 2603 if (node->eb->start == bytenr)
2604 goto next;
5d4f98a2
YZ		 2605 }
2606
2607 blocksize = btrfs_level_size(root, node->level);
2608 generation = btrfs_node_ptr_generation(upper->eb, slot);
2609 eb = read_tree_block(root, bytenr, blocksize, generation);
416bc658
JB		 2610 if (!eb || !extent_buffer_uptodate(eb)) {
2611 free_extent_buffer(eb);
97d9a8a4
TI		 2612 err = -EIO;
2613 goto next;
2614 }
5d4f98a2
YZ		 2615 btrfs_tree_lock(eb);
2616 btrfs_set_lock_blocking(eb);
2617
2618 if (!node->eb) {
2619 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2620 slot, &eb);
3fd0a558
YZ		 2621 btrfs_tree_unlock(eb);
2622 free_extent_buffer(eb);
5d4f98a2
YZ		 2623 if (ret < 0) {
2624 err = ret;
3fd0a558 2625 goto next;
5d4f98a2 2626 }
3fd0a558 2627 BUG_ON(node->eb != eb);
5d4f98a2
YZ		 2628 } else {
2629 btrfs_set_node_blockptr(upper->eb, slot,
2630 node->eb->start);
2631 btrfs_set_node_ptr_generation(upper->eb, slot,
2632 trans->transid);
2633 btrfs_mark_buffer_dirty(upper->eb);
2634
2635 ret = btrfs_inc_extent_ref(trans, root,
2636 node->eb->start, blocksize,
2637 upper->eb->start,
2638 btrfs_header_owner(upper->eb),
66d7e7f0 2639 node->level, 0, 1);
5d4f98a2
YZ		 2640 BUG_ON(ret);
2641
2642 ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
2643 BUG_ON(ret);
5d4f98a2 2644 }
3fd0a558
YZ		 2645next:
2646 if (!upper->pending)
2647 drop_node_buffer(upper);
2648 else
2649 unlock_node_buffer(upper);
2650 if (err)
2651 break;
5d4f98a2 2652 }
3fd0a558
YZ		 2653
2654 if (!err && node->pending) {
2655 drop_node_buffer(node);
2656 list_move_tail(&node->list, &rc->backref_cache.changed);
2657 node->pending = 0;
2658 }
2659
5d4f98a2 2660 path->lowest_level = 0;
3fd0a558 2661 BUG_ON(err == -ENOSPC);
5d4f98a2
YZ		 2662 return err;
2663}
2664
2665static int link_to_upper(struct btrfs_trans_handle *trans,
3fd0a558 2666 struct reloc_control *rc,
5d4f98a2
YZ		 2667 struct backref_node *node,
2668 struct btrfs_path *path)
2669{
2670 struct btrfs_key key;
5d4f98a2
YZ		 2671
2672 btrfs_node_key_to_cpu(node->eb, &key, 0);
3fd0a558 2673 return do_relocation(trans, rc, node, &key, path, 0);
5d4f98a2
YZ		 2674}
2675
2676static int finish_pending_nodes(struct btrfs_trans_handle *trans,
3fd0a558
YZ		 2677 struct reloc_control *rc,
2678 struct btrfs_path *path, int err)
5d4f98a2 2679{
3fd0a558
YZ		 2680 LIST_HEAD(list);
2681 struct backref_cache *cache = &rc->backref_cache;
5d4f98a2
YZ		 2682 struct backref_node *node;
2683 int level;
2684 int ret;
5d4f98a2
YZ		 2685
2686 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2687 while (!list_empty(&cache->pending[level])) {
2688 node = list_entry(cache->pending[level].next,
3fd0a558
YZ		 2689 struct backref_node, list);
2690 list_move_tail(&node->list, &list);
2691 BUG_ON(!node->pending);
5d4f98a2 2692
3fd0a558
YZ		 2693 if (!err) {
2694 ret = link_to_upper(trans, rc, node, path);
2695 if (ret < 0)
2696 err = ret;
2697 }
5d4f98a2 2698 }
3fd0a558 2699 list_splice_init(&list, &cache->pending[level]);
5d4f98a2 2700 }
5d4f98a2
YZ		 2701 return err;
2702}
2703
2704static void mark_block_processed(struct reloc_control *rc,
3fd0a558
YZ		 2705 u64 bytenr, u32 blocksize)
2706{
2707 set_extent_bits(&rc->processed_blocks, bytenr, bytenr + blocksize - 1,
2708 EXTENT_DIRTY, GFP_NOFS);
2709}
2710
2711static void __mark_block_processed(struct reloc_control *rc,
2712 struct backref_node *node)
5d4f98a2
YZ		 2713{
2714 u32 blocksize;
2715 if (node->level == 0 ||
2716 in_block_group(node->bytenr, rc->block_group)) {
2717 blocksize = btrfs_level_size(rc->extent_root, node->level);
3fd0a558 2718 mark_block_processed(rc, node->bytenr, blocksize);
5d4f98a2
YZ		 2719 }
2720 node->processed = 1;
2721}
2722
2723/*
2724 * mark a block and all blocks directly/indirectly reference the block
2725 * as processed.
2726 */
2727static void update_processed_blocks(struct reloc_control *rc,
2728 struct backref_node *node)
2729{
2730 struct backref_node *next = node;
2731 struct backref_edge *edge;
2732 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2733 int index = 0;
2734
2735 while (next) {
2736 cond_resched();
2737 while (1) {
2738 if (next->processed)
2739 break;
2740
3fd0a558 2741 __mark_block_processed(rc, next);
5d4f98a2
YZ		 2742
2743 if (list_empty(&next->upper))
2744 break;
2745
2746 edge = list_entry(next->upper.next,
2747 struct backref_edge, list[LOWER]);
2748 edges[index++] = edge;
2749 next = edge->node[UPPER];
2750 }
2751 next = walk_down_backref(edges, &index);
2752 }
2753}
2754
3fd0a558
YZ		 2755static int tree_block_processed(u64 bytenr, u32 blocksize,
2756 struct reloc_control *rc)
2757{
2758 if (test_range_bit(&rc->processed_blocks, bytenr,
2759 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
2760 return 1;
2761 return 0;
5d4f98a2
YZ		 2762}
2763
2764static int get_tree_block_key(struct reloc_control *rc,
2765 struct tree_block *block)
2766{
2767 struct extent_buffer *eb;
2768
2769 BUG_ON(block->key_ready);
2770 eb = read_tree_block(rc->extent_root, block->bytenr,
2771 block->key.objectid, block->key.offset);
416bc658
JB		 2772 if (!eb || !extent_buffer_uptodate(eb)) {
2773 free_extent_buffer(eb);
2774 return -EIO;
2775 }
5d4f98a2
YZ		 2776 WARN_ON(btrfs_header_level(eb) != block->level);
2777 if (block->level == 0)
2778 btrfs_item_key_to_cpu(eb, &block->key, 0);
2779 else
2780 btrfs_node_key_to_cpu(eb, &block->key, 0);
2781 free_extent_buffer(eb);
2782 block->key_ready = 1;
2783 return 0;
2784}
2785
2786static int reada_tree_block(struct reloc_control *rc,
2787 struct tree_block *block)
2788{
2789 BUG_ON(block->key_ready);
3173a18f
JB		 2790 if (block->key.type == BTRFS_METADATA_ITEM_KEY)
2791 readahead_tree_block(rc->extent_root, block->bytenr,
2792 block->key.objectid,
2793 rc->extent_root->leafsize);
2794 else
2795 readahead_tree_block(rc->extent_root, block->bytenr,
2796 block->key.objectid, block->key.offset);
5d4f98a2
YZ		 2797 return 0;
2798}
2799
2800/*
2801 * helper function to relocate a tree block
2802 */
2803static int relocate_tree_block(struct btrfs_trans_handle *trans,
2804 struct reloc_control *rc,
2805 struct backref_node *node,
2806 struct btrfs_key *key,
2807 struct btrfs_path *path)
2808{
2809 struct btrfs_root *root;
3fd0a558
YZ		 2810 int release = 0;
2811 int ret = 0;
2812
2813 if (!node)
2814 return 0;
5d4f98a2 2815
3fd0a558 2816 BUG_ON(node->processed);
5d4f98a2 2817 root = select_one_root(trans, node);
3fd0a558 2818 if (root == ERR_PTR(-ENOENT)) {
5d4f98a2 2819 update_processed_blocks(rc, node);
3fd0a558 2820 goto out;
5d4f98a2
YZ		 2821 }
2822
3fd0a558
YZ		 2823 if (!root || root->ref_cows) {
2824 ret = reserve_metadata_space(trans, rc, node);
2825 if (ret)
5d4f98a2 2826 goto out;
3fd0a558 2827 release = 1;
5d4f98a2
YZ		 2828 }
2829
3fd0a558
YZ		 2830 if (root) {
2831 if (root->ref_cows) {
2832 BUG_ON(node->new_bytenr);
2833 BUG_ON(!list_empty(&node->list));
2834 btrfs_record_root_in_trans(trans, root);
2835 root = root->reloc_root;
2836 node->new_bytenr = root->node->start;
2837 node->root = root;
2838 list_add_tail(&node->list, &rc->backref_cache.changed);
2839 } else {
2840 path->lowest_level = node->level;
2841 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
b3b4aa74 2842 btrfs_release_path(path);
3fd0a558
YZ		 2843 if (ret > 0)
2844 ret = 0;
2845 }
2846 if (!ret)
2847 update_processed_blocks(rc, node);
2848 } else {
2849 ret = do_relocation(trans, rc, node, key, path, 1);
2850 }
5d4f98a2 2851out:
3fd0a558
YZ		 2852 if (ret || node->level == 0 || node->cowonly) {
2853 if (release)
2854 release_metadata_space(rc, node);
2855 remove_backref_node(&rc->backref_cache, node);
2856 }
5d4f98a2
YZ		 2857 return ret;
2858}
2859
2860/*
2861 * relocate a list of blocks
2862 */
2863static noinline_for_stack
2864int relocate_tree_blocks(struct btrfs_trans_handle *trans,
2865 struct reloc_control *rc, struct rb_root *blocks)
2866{
5d4f98a2
YZ		 2867 struct backref_node *node;
2868 struct btrfs_path *path;
2869 struct tree_block *block;
2870 struct rb_node *rb_node;
5d4f98a2
YZ		 2871 int ret;
2872 int err = 0;
2873
2874 path = btrfs_alloc_path();
e1a12670
LB		 2875 if (!path) {
2876 err = -ENOMEM;
34c2b290 2877 goto out_free_blocks;
e1a12670 2878 }
5d4f98a2 2879
5d4f98a2
YZ		 2880 rb_node = rb_first(blocks);
2881 while (rb_node) {
2882 block = rb_entry(rb_node, struct tree_block, rb_node);
5d4f98a2
YZ		 2883 if (!block->key_ready)
2884 reada_tree_block(rc, block);
2885 rb_node = rb_next(rb_node);
2886 }
2887
2888 rb_node = rb_first(blocks);
2889 while (rb_node) {
2890 block = rb_entry(rb_node, struct tree_block, rb_node);
34c2b290
DS		 2891 if (!block->key_ready) {
2892 err = get_tree_block_key(rc, block);
2893 if (err)
2894 goto out_free_path;
2895 }
5d4f98a2
YZ		 2896 rb_node = rb_next(rb_node);
2897 }
2898
2899 rb_node = rb_first(blocks);
2900 while (rb_node) {
2901 block = rb_entry(rb_node, struct tree_block, rb_node);
2902
3fd0a558 2903 node = build_backref_tree(rc, &block->key,
5d4f98a2
YZ		 2904 block->level, block->bytenr);
2905 if (IS_ERR(node)) {
2906 err = PTR_ERR(node);
2907 goto out;
2908 }
2909
2910 ret = relocate_tree_block(trans, rc, node, &block->key,
2911 path);
2912 if (ret < 0) {
3fd0a558
YZ		 2913 if (ret != -EAGAIN || rb_node == rb_first(blocks))
2914 err = ret;
5d4f98a2
YZ		 2915 goto out;
2916 }
5d4f98a2
YZ		 2917 rb_node = rb_next(rb_node);
2918 }
5d4f98a2 2919out:
3fd0a558 2920 err = finish_pending_nodes(trans, rc, path, err);
5d4f98a2 2921
34c2b290 2922out_free_path:
5d4f98a2 2923 btrfs_free_path(path);
34c2b290 2924out_free_blocks:
e1a12670 2925 free_block_list(blocks);
5d4f98a2
YZ		 2926 return err;
2927}
2928
efa56464
YZ		 2929static noinline_for_stack
2930int prealloc_file_extent_cluster(struct inode *inode,
2931 struct file_extent_cluster *cluster)
2932{
2933 u64 alloc_hint = 0;
2934 u64 start;
2935 u64 end;
2936 u64 offset = BTRFS_I(inode)->index_cnt;
2937 u64 num_bytes;
2938 int nr = 0;
2939 int ret = 0;
2940
2941 BUG_ON(cluster->start != cluster->boundary[0]);
2942 mutex_lock(&inode->i_mutex);
2943
2944 ret = btrfs_check_data_free_space(inode, cluster->end +
2945 1 - cluster->start);
2946 if (ret)
2947 goto out;
2948
2949 while (nr < cluster->nr) {
2950 start = cluster->boundary[nr] - offset;
2951 if (nr + 1 < cluster->nr)
2952 end = cluster->boundary[nr + 1] - 1 - offset;
2953 else
2954 end = cluster->end - offset;
2955
d0082371 2956 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
efa56464
YZ		 2957 num_bytes = end + 1 - start;
2958 ret = btrfs_prealloc_file_range(inode, 0, start,
2959 num_bytes, num_bytes,
2960 end + 1, &alloc_hint);
d0082371 2961 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
efa56464
YZ		 2962 if (ret)
2963 break;
2964 nr++;
2965 }
2966 btrfs_free_reserved_data_space(inode, cluster->end +
2967 1 - cluster->start);
2968out:
2969 mutex_unlock(&inode->i_mutex);
2970 return ret;
2971}
2972
5d4f98a2 2973static noinline_for_stack
0257bb82
YZ		 2974int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
2975 u64 block_start)
2976{
2977 struct btrfs_root *root = BTRFS_I(inode)->root;
2978 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
2979 struct extent_map *em;
2980 int ret = 0;
2981
172ddd60 2982 em = alloc_extent_map();
0257bb82
YZ		 2983 if (!em)
2984 return -ENOMEM;
2985
2986 em->start = start;
2987 em->len = end + 1 - start;
2988 em->block_len = em->len;
2989 em->block_start = block_start;
2990 em->bdev = root->fs_info->fs_devices->latest_bdev;
2991 set_bit(EXTENT_FLAG_PINNED, &em->flags);
2992
d0082371 2993 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
0257bb82
YZ		 2994 while (1) {
2995 write_lock(&em_tree->lock);
09a2a8f9 2996 ret = add_extent_mapping(em_tree, em, 0);
0257bb82
YZ		 2997 write_unlock(&em_tree->lock);
2998 if (ret != -EEXIST) {
2999 free_extent_map(em);
3000 break;
3001 }
3002 btrfs_drop_extent_cache(inode, start, end, 0);
3003 }
d0082371 3004 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
0257bb82
YZ		 3005 return ret;
3006}
3007
3008static int relocate_file_extent_cluster(struct inode *inode,
3009 struct file_extent_cluster *cluster)
5d4f98a2
YZ		 3010{
3011 u64 page_start;
3012 u64 page_end;
0257bb82
YZ		 3013 u64 offset = BTRFS_I(inode)->index_cnt;
3014 unsigned long index;
5d4f98a2 3015 unsigned long last_index;
5d4f98a2
YZ		 3016 struct page *page;
3017 struct file_ra_state *ra;
3b16a4e3 3018 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
0257bb82 3019 int nr = 0;
5d4f98a2
YZ		 3020 int ret = 0;
3021
0257bb82
YZ		 3022 if (!cluster->nr)
3023 return 0;
3024
5d4f98a2
YZ		 3025 ra = kzalloc(sizeof(*ra), GFP_NOFS);
3026 if (!ra)
3027 return -ENOMEM;
3028
efa56464
YZ		 3029 ret = prealloc_file_extent_cluster(inode, cluster);
3030 if (ret)
3031 goto out;
0257bb82 3032
efa56464 3033 file_ra_state_init(ra, inode->i_mapping);
5d4f98a2 3034
0257bb82
YZ		 3035 ret = setup_extent_mapping(inode, cluster->start - offset,
3036 cluster->end - offset, cluster->start);
5d4f98a2 3037 if (ret)
efa56464 3038 goto out;
5d4f98a2 3039
efa56464
YZ		 3040 index = (cluster->start - offset) >> PAGE_CACHE_SHIFT;
3041 last_index = (cluster->end - offset) >> PAGE_CACHE_SHIFT;
0257bb82 3042 while (index <= last_index) {
efa56464
YZ		 3043 ret = btrfs_delalloc_reserve_metadata(inode, PAGE_CACHE_SIZE);
3044 if (ret)
3045 goto out;
3046
0257bb82 3047 page = find_lock_page(inode->i_mapping, index);
5d4f98a2 3048 if (!page) {
0257bb82
YZ		 3049 page_cache_sync_readahead(inode->i_mapping,
3050 ra, NULL, index,
3051 last_index + 1 - index);
a94733d0 3052 page = find_or_create_page(inode->i_mapping, index,
3b16a4e3 3053 mask);
0257bb82 3054 if (!page) {
efa56464
YZ		 3055 btrfs_delalloc_release_metadata(inode,
3056 PAGE_CACHE_SIZE);
0257bb82 3057 ret = -ENOMEM;
efa56464 3058 goto out;
0257bb82 3059 }
5d4f98a2 3060 }
0257bb82
YZ		 3061
3062 if (PageReadahead(page)) {
3063 page_cache_async_readahead(inode->i_mapping,
3064 ra, NULL, page, index,
3065 last_index + 1 - index);
3066 }
3067
5d4f98a2
YZ		 3068 if (!PageUptodate(page)) {
3069 btrfs_readpage(NULL, page);
3070 lock_page(page);
3071 if (!PageUptodate(page)) {
3072 unlock_page(page);
3073 page_cache_release(page);
efa56464
YZ		 3074 btrfs_delalloc_release_metadata(inode,
3075 PAGE_CACHE_SIZE);
5d4f98a2 3076 ret = -EIO;
efa56464 3077 goto out;
5d4f98a2
YZ		 3078 }
3079 }
5d4f98a2 3080
4eee4fa4 3081 page_start = page_offset(page);
5d4f98a2 3082 page_end = page_start + PAGE_CACHE_SIZE - 1;
0257bb82 3083
d0082371 3084 lock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end);
0257bb82 3085
5d4f98a2
YZ		 3086 set_page_extent_mapped(page);
3087
0257bb82
YZ		 3088 if (nr < cluster->nr &&
3089 page_start + offset == cluster->boundary[nr]) {
3090 set_extent_bits(&BTRFS_I(inode)->io_tree,
3091 page_start, page_end,
5d4f98a2 3092 EXTENT_BOUNDARY, GFP_NOFS);
0257bb82
YZ		 3093 nr++;
3094 }
5d4f98a2 3095
efa56464 3096 btrfs_set_extent_delalloc(inode, page_start, page_end, NULL);
5d4f98a2 3097 set_page_dirty(page);
5d4f98a2 3098
0257bb82 3099 unlock_extent(&BTRFS_I(inode)->io_tree,
d0082371 3100 page_start, page_end);
5d4f98a2
YZ		 3101 unlock_page(page);
3102 page_cache_release(page);
0257bb82
YZ		 3103
3104 index++;
efa56464
YZ		 3105 balance_dirty_pages_ratelimited(inode->i_mapping);
3106 btrfs_throttle(BTRFS_I(inode)->root);
5d4f98a2 3107 }
0257bb82 3108 WARN_ON(nr != cluster->nr);
efa56464 3109out:
5d4f98a2 3110 kfree(ra);
5d4f98a2
YZ		 3111 return ret;
3112}
3113
3114static noinline_for_stack
0257bb82
YZ		 3115int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
3116 struct file_extent_cluster *cluster)
5d4f98a2 3117{
0257bb82 3118 int ret;
5d4f98a2 3119
0257bb82
YZ		 3120 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
3121 ret = relocate_file_extent_cluster(inode, cluster);
3122 if (ret)
3123 return ret;
3124 cluster->nr = 0;
5d4f98a2 3125 }
5d4f98a2 3126
0257bb82
YZ		 3127 if (!cluster->nr)
3128 cluster->start = extent_key->objectid;
3129 else
3130 BUG_ON(cluster->nr >= MAX_EXTENTS);
3131 cluster->end = extent_key->objectid + extent_key->offset - 1;
3132 cluster->boundary[cluster->nr] = extent_key->objectid;
3133 cluster->nr++;
3134
3135 if (cluster->nr >= MAX_EXTENTS) {
3136 ret = relocate_file_extent_cluster(inode, cluster);
3137 if (ret)
3138 return ret;
3139 cluster->nr = 0;
3140 }
3141 return 0;
5d4f98a2
YZ		 3142}
3143
3144#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3145static int get_ref_objectid_v0(struct reloc_control *rc,
3146 struct btrfs_path *path,
3147 struct btrfs_key *extent_key,
3148 u64 *ref_objectid, int *path_change)
3149{
3150 struct btrfs_key key;
3151 struct extent_buffer *leaf;
3152 struct btrfs_extent_ref_v0 *ref0;
3153 int ret;
3154 int slot;
3155
3156 leaf = path->nodes[0];
3157 slot = path->slots[0];
3158 while (1) {
3159 if (slot >= btrfs_header_nritems(leaf)) {
3160 ret = btrfs_next_leaf(rc->extent_root, path);
3161 if (ret < 0)
3162 return ret;
3163 BUG_ON(ret > 0);
3164 leaf = path->nodes[0];
3165 slot = path->slots[0];
3166 if (path_change)
3167 *path_change = 1;
3168 }
3169 btrfs_item_key_to_cpu(leaf, &key, slot);
3170 if (key.objectid != extent_key->objectid)
3171 return -ENOENT;
3172
3173 if (key.type != BTRFS_EXTENT_REF_V0_KEY) {
3174 slot++;
3175 continue;
3176 }
3177 ref0 = btrfs_item_ptr(leaf, slot,
3178 struct btrfs_extent_ref_v0);
3179 *ref_objectid = btrfs_ref_objectid_v0(leaf, ref0);
3180 break;
3181 }
3182 return 0;
3183}
3184#endif
3185
3186/*
3187 * helper to add a tree block to the list.
3188 * the major work is getting the generation and level of the block
3189 */
3190static int add_tree_block(struct reloc_control *rc,
3191 struct btrfs_key *extent_key,
3192 struct btrfs_path *path,
3193 struct rb_root *blocks)
3194{
3195 struct extent_buffer *eb;
3196 struct btrfs_extent_item *ei;
3197 struct btrfs_tree_block_info *bi;
3198 struct tree_block *block;
3199 struct rb_node *rb_node;
3200 u32 item_size;
3201 int level = -1;
3202 int generation;
3203
3204 eb = path->nodes[0];
3205 item_size = btrfs_item_size_nr(eb, path->slots[0]);
3206
3173a18f
JB		 3207 if (extent_key->type == BTRFS_METADATA_ITEM_KEY ||
3208 item_size >= sizeof(*ei) + sizeof(*bi)) {
5d4f98a2
YZ		 3209 ei = btrfs_item_ptr(eb, path->slots[0],
3210 struct btrfs_extent_item);
3173a18f
JB		 3211 if (extent_key->type == BTRFS_EXTENT_ITEM_KEY) {
3212 bi = (struct btrfs_tree_block_info *)(ei + 1);
3213 level = btrfs_tree_block_level(eb, bi);
3214 } else {
3215 level = (int)extent_key->offset;
3216 }
5d4f98a2 3217 generation = btrfs_extent_generation(eb, ei);
5d4f98a2
YZ		 3218 } else {
3219#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3220 u64 ref_owner;
3221 int ret;
3222
3223 BUG_ON(item_size != sizeof(struct btrfs_extent_item_v0));
3224 ret = get_ref_objectid_v0(rc, path, extent_key,
3225 &ref_owner, NULL);
411fc6bc
AK		 3226 if (ret < 0)
3227 return ret;
5d4f98a2
YZ		 3228 BUG_ON(ref_owner >= BTRFS_MAX_LEVEL);
3229 level = (int)ref_owner;
3230 /* FIXME: get real generation */
3231 generation = 0;
3232#else
3233 BUG();
3234#endif
3235 }
3236
b3b4aa74 3237 btrfs_release_path(path);
5d4f98a2
YZ		 3238
3239 BUG_ON(level == -1);
3240
3241 block = kmalloc(sizeof(*block), GFP_NOFS);
3242 if (!block)
3243 return -ENOMEM;
3244
3245 block->bytenr = extent_key->objectid;
3173a18f 3246 block->key.objectid = rc->extent_root->leafsize;
5d4f98a2
YZ		 3247 block->key.offset = generation;
3248 block->level = level;
3249 block->key_ready = 0;
3250
3251 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
43c04fb1
JM		 3252 if (rb_node)
3253 backref_tree_panic(rb_node, -EEXIST, block->bytenr);
5d4f98a2
YZ		 3254
3255 return 0;
3256}
3257
3258/*
3259 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
3260 */
3261static int __add_tree_block(struct reloc_control *rc,
3262 u64 bytenr, u32 blocksize,
3263 struct rb_root *blocks)
3264{
3265 struct btrfs_path *path;
3266 struct btrfs_key key;
3267 int ret;
3268
3269 if (tree_block_processed(bytenr, blocksize, rc))
3270 return 0;
3271
3272 if (tree_search(blocks, bytenr))
3273 return 0;
3274
3275 path = btrfs_alloc_path();
3276 if (!path)
3277 return -ENOMEM;
3278
3279 key.objectid = bytenr;
3280 key.type = BTRFS_EXTENT_ITEM_KEY;
3281 key.offset = blocksize;
3282
3283 path->search_commit_root = 1;
3284 path->skip_locking = 1;
3285 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
3286 if (ret < 0)
3287 goto out;
5d4f98a2
YZ		 3288
3289 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
3173a18f
JB		 3290 if (ret > 0) {
3291 if (key.objectid == bytenr &&
3292 key.type == BTRFS_METADATA_ITEM_KEY)
3293 ret = 0;
3294 }
3295 BUG_ON(ret);
3296
5d4f98a2
YZ		 3297 ret = add_tree_block(rc, &key, path, blocks);
3298out:
3299 btrfs_free_path(path);
3300 return ret;
3301}
3302
3303/*
3304 * helper to check if the block use full backrefs for pointers in it
3305 */
3306static int block_use_full_backref(struct reloc_control *rc,
3307 struct extent_buffer *eb)
3308{
5d4f98a2
YZ		 3309 u64 flags;
3310 int ret;
3311
3312 if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) ||
3313 btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV)
3314 return 1;
3315
3fd0a558 3316 ret = btrfs_lookup_extent_info(NULL, rc->extent_root,
3173a18f
JB		 3317 eb->start, btrfs_header_level(eb), 1,
3318 NULL, &flags);
5d4f98a2
YZ		 3319 BUG_ON(ret);
3320
5d4f98a2
YZ		 3321 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
3322 ret = 1;
3323 else
3324 ret = 0;
5d4f98a2
YZ		 3325 return ret;
3326}
3327
0af3d00b
JB		 3328static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
3329 struct inode *inode, u64 ino)
3330{
3331 struct btrfs_key key;
3332 struct btrfs_path *path;
3333 struct btrfs_root *root = fs_info->tree_root;
3334 struct btrfs_trans_handle *trans;
0af3d00b
JB		 3335 int ret = 0;
3336
3337 if (inode)
3338 goto truncate;
3339
3340 key.objectid = ino;
3341 key.type = BTRFS_INODE_ITEM_KEY;
3342 key.offset = 0;
3343
3344 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
f54fb859
TI		 3345 if (IS_ERR(inode) || is_bad_inode(inode)) {
3346 if (!IS_ERR(inode))
0af3d00b
JB		 3347 iput(inode);
3348 return -ENOENT;
3349 }
3350
3351truncate:
7b61cd92
MX		 3352 ret = btrfs_check_trunc_cache_free_space(root,
3353 &fs_info->global_block_rsv);
3354 if (ret)
3355 goto out;
3356
0af3d00b
JB		 3357 path = btrfs_alloc_path();
3358 if (!path) {
3359 ret = -ENOMEM;
3360 goto out;
3361 }
3362
7a7eaa40 3363 trans = btrfs_join_transaction(root);
0af3d00b
JB		 3364 if (IS_ERR(trans)) {
3365 btrfs_free_path(path);
3612b495 3366 ret = PTR_ERR(trans);
0af3d00b
JB		 3367 goto out;
3368 }
3369
3370 ret = btrfs_truncate_free_space_cache(root, trans, path, inode);
3371
3372 btrfs_free_path(path);
0af3d00b 3373 btrfs_end_transaction(trans, root);
b53d3f5d 3374 btrfs_btree_balance_dirty(root);
0af3d00b
JB		 3375out:
3376 iput(inode);
3377 return ret;
3378}
3379
5d4f98a2
YZ		 3380/*
3381 * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY
3382 * this function scans fs tree to find blocks reference the data extent
3383 */
3384static int find_data_references(struct reloc_control *rc,
3385 struct btrfs_key *extent_key,
3386 struct extent_buffer *leaf,
3387 struct btrfs_extent_data_ref *ref,
3388 struct rb_root *blocks)
3389{
3390 struct btrfs_path *path;
3391 struct tree_block *block;
3392 struct btrfs_root *root;
3393 struct btrfs_file_extent_item *fi;
3394 struct rb_node *rb_node;
3395 struct btrfs_key key;
3396 u64 ref_root;
3397 u64 ref_objectid;
3398 u64 ref_offset;
3399 u32 ref_count;
3400 u32 nritems;
3401 int err = 0;
3402 int added = 0;
3403 int counted;
3404 int ret;
3405
5d4f98a2
YZ		 3406 ref_root = btrfs_extent_data_ref_root(leaf, ref);
3407 ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
3408 ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
3409 ref_count = btrfs_extent_data_ref_count(leaf, ref);
3410
0af3d00b
JB		 3411 /*
3412 * This is an extent belonging to the free space cache, lets just delete
3413 * it and redo the search.
3414 */
3415 if (ref_root == BTRFS_ROOT_TREE_OBJECTID) {
3416 ret = delete_block_group_cache(rc->extent_root->fs_info,
3417 NULL, ref_objectid);
3418 if (ret != -ENOENT)
3419 return ret;
3420 ret = 0;
3421 }
3422
3423 path = btrfs_alloc_path();
3424 if (!path)
3425 return -ENOMEM;
026fd317 3426 path->reada = 1;
0af3d00b 3427
5d4f98a2
YZ		 3428 root = read_fs_root(rc->extent_root->fs_info, ref_root);
3429 if (IS_ERR(root)) {
3430 err = PTR_ERR(root);
3431 goto out;
3432 }
3433
3434 key.objectid = ref_objectid;
5d4f98a2 3435 key.type = BTRFS_EXTENT_DATA_KEY;
84850e8d
YZ		 3436 if (ref_offset > ((u64)-1 << 32))
3437 key.offset = 0;
3438 else
3439 key.offset = ref_offset;
5d4f98a2
YZ		 3440
3441 path->search_commit_root = 1;
3442 path->skip_locking = 1;
3443 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3444 if (ret < 0) {
3445 err = ret;
3446 goto out;
3447 }
3448
3449 leaf = path->nodes[0];
3450 nritems = btrfs_header_nritems(leaf);
3451 /*
3452 * the references in tree blocks that use full backrefs
3453 * are not counted in
3454 */
3455 if (block_use_full_backref(rc, leaf))
3456 counted = 0;
3457 else
3458 counted = 1;
3459 rb_node = tree_search(blocks, leaf->start);
3460 if (rb_node) {
3461 if (counted)
3462 added = 1;
3463 else
3464 path->slots[0] = nritems;
3465 }
3466
3467 while (ref_count > 0) {
3468 while (path->slots[0] >= nritems) {
3469 ret = btrfs_next_leaf(root, path);
3470 if (ret < 0) {
3471 err = ret;
3472 goto out;
3473 }
3474 if (ret > 0) {
3475 WARN_ON(1);
3476 goto out;
3477 }
3478
3479 leaf = path->nodes[0];
3480 nritems = btrfs_header_nritems(leaf);
3481 added = 0;
3482
3483 if (block_use_full_backref(rc, leaf))
3484 counted = 0;
3485 else
3486 counted = 1;
3487 rb_node = tree_search(blocks, leaf->start);
3488 if (rb_node) {
3489 if (counted)
3490 added = 1;
3491 else
3492 path->slots[0] = nritems;
3493 }
3494 }
3495
3496 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3497 if (key.objectid != ref_objectid ||
3498 key.type != BTRFS_EXTENT_DATA_KEY) {
3499 WARN_ON(1);
3500 break;
3501 }
3502
3503 fi = btrfs_item_ptr(leaf, path->slots[0],
3504 struct btrfs_file_extent_item);
3505
3506 if (btrfs_file_extent_type(leaf, fi) ==
3507 BTRFS_FILE_EXTENT_INLINE)
3508 goto next;
3509
3510 if (btrfs_file_extent_disk_bytenr(leaf, fi) !=
3511 extent_key->objectid)
3512 goto next;
3513
3514 key.offset -= btrfs_file_extent_offset(leaf, fi);
3515 if (key.offset != ref_offset)
3516 goto next;
3517
3518 if (counted)
3519 ref_count--;
3520 if (added)
3521 goto next;
3522
3523 if (!tree_block_processed(leaf->start, leaf->len, rc)) {
3524 block = kmalloc(sizeof(*block), GFP_NOFS);
3525 if (!block) {
3526 err = -ENOMEM;
3527 break;
3528 }
3529 block->bytenr = leaf->start;
3530 btrfs_item_key_to_cpu(leaf, &block->key, 0);
3531 block->level = 0;
3532 block->key_ready = 1;
3533 rb_node = tree_insert(blocks, block->bytenr,
3534 &block->rb_node);
43c04fb1
JM		 3535 if (rb_node)
3536 backref_tree_panic(rb_node, -EEXIST,
3537 block->bytenr);
5d4f98a2
YZ		 3538 }
3539 if (counted)
3540 added = 1;
3541 else
3542 path->slots[0] = nritems;
3543next:
3544 path->slots[0]++;
3545
3546 }
3547out:
3548 btrfs_free_path(path);
3549 return err;
3550}
3551
3552/*
2c016dc2 3553 * helper to find all tree blocks that reference a given data extent
5d4f98a2
YZ		 3554 */
3555static noinline_for_stack
3556int add_data_references(struct reloc_control *rc,
3557 struct btrfs_key *extent_key,
3558 struct btrfs_path *path,
3559 struct rb_root *blocks)
3560{
3561 struct btrfs_key key;
3562 struct extent_buffer *eb;
3563 struct btrfs_extent_data_ref *dref;
3564 struct btrfs_extent_inline_ref *iref;
3565 unsigned long ptr;
3566 unsigned long end;
3fd0a558 3567 u32 blocksize = btrfs_level_size(rc->extent_root, 0);
5d4f98a2
YZ		 3568 int ret;
3569 int err = 0;
3570
5d4f98a2
YZ		 3571 eb = path->nodes[0];
3572 ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
3573 end = ptr + btrfs_item_size_nr(eb, path->slots[0]);
3574#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3575 if (ptr + sizeof(struct btrfs_extent_item_v0) == end)
3576 ptr = end;
3577 else
3578#endif
3579 ptr += sizeof(struct btrfs_extent_item);
3580
3581 while (ptr < end) {
3582 iref = (struct btrfs_extent_inline_ref *)ptr;
3583 key.type = btrfs_extent_inline_ref_type(eb, iref);
3584 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3585 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
3586 ret = __add_tree_block(rc, key.offset, blocksize,
3587 blocks);
3588 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3589 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
3590 ret = find_data_references(rc, extent_key,
3591 eb, dref, blocks);
3592 } else {
3593 BUG();
3594 }
3595 ptr += btrfs_extent_inline_ref_size(key.type);
3596 }
3597 WARN_ON(ptr > end);
3598
3599 while (1) {
3600 cond_resched();
3601 eb = path->nodes[0];
3602 if (path->slots[0] >= btrfs_header_nritems(eb)) {
3603 ret = btrfs_next_leaf(rc->extent_root, path);
3604 if (ret < 0) {
3605 err = ret;
3606 break;
3607 }
3608 if (ret > 0)
3609 break;
3610 eb = path->nodes[0];
3611 }
3612
3613 btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
3614 if (key.objectid != extent_key->objectid)
3615 break;
3616
3617#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3618 if (key.type == BTRFS_SHARED_DATA_REF_KEY ||
3619 key.type == BTRFS_EXTENT_REF_V0_KEY) {
3620#else
3621 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
3622 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3623#endif
3624 ret = __add_tree_block(rc, key.offset, blocksize,
3625 blocks);
3626 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3627 dref = btrfs_item_ptr(eb, path->slots[0],
3628 struct btrfs_extent_data_ref);
3629 ret = find_data_references(rc, extent_key,
3630 eb, dref, blocks);
3631 } else {
3632 ret = 0;
3633 }
3634 if (ret) {
3635 err = ret;
3636 break;
3637 }
3638 path->slots[0]++;
3639 }
b3b4aa74 3640 btrfs_release_path(path);
5d4f98a2
YZ		 3641 if (err)
3642 free_block_list(blocks);
3643 return err;
3644}
3645
3646/*
2c016dc2 3647 * helper to find next unprocessed extent
5d4f98a2
YZ		 3648 */
3649static noinline_for_stack
3650int find_next_extent(struct btrfs_trans_handle *trans,
3fd0a558
YZ		 3651 struct reloc_control *rc, struct btrfs_path *path,
3652 struct btrfs_key *extent_key)
5d4f98a2
YZ		 3653{
3654 struct btrfs_key key;
3655 struct extent_buffer *leaf;
3656 u64 start, end, last;
3657 int ret;
3658
3659 last = rc->block_group->key.objectid + rc->block_group->key.offset;
3660 while (1) {
3661 cond_resched();
3662 if (rc->search_start >= last) {
3663 ret = 1;
3664 break;
3665 }
3666
3667 key.objectid = rc->search_start;
3668 key.type = BTRFS_EXTENT_ITEM_KEY;
3669 key.offset = 0;
3670
3671 path->search_commit_root = 1;
3672 path->skip_locking = 1;
3673 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3674 0, 0);
3675 if (ret < 0)
3676 break;
3677next:
3678 leaf = path->nodes[0];
3679 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3680 ret = btrfs_next_leaf(rc->extent_root, path);
3681 if (ret != 0)
3682 break;
3683 leaf = path->nodes[0];
3684 }
3685
3686 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3687 if (key.objectid >= last) {
3688 ret = 1;
3689 break;
3690 }
3691
3173a18f
JB		 3692 if (key.type != BTRFS_EXTENT_ITEM_KEY &&
3693 key.type != BTRFS_METADATA_ITEM_KEY) {
3694 path->slots[0]++;
3695 goto next;
3696 }
3697
3698 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
5d4f98a2
YZ		 3699 key.objectid + key.offset <= rc->search_start) {
3700 path->slots[0]++;
3701 goto next;
3702 }
3703
3173a18f
JB		 3704 if (key.type == BTRFS_METADATA_ITEM_KEY &&
3705 key.objectid + rc->extent_root->leafsize <=
3706 rc->search_start) {
3707 path->slots[0]++;
3708 goto next;
3709 }
3710
5d4f98a2
YZ		 3711 ret = find_first_extent_bit(&rc->processed_blocks,
3712 key.objectid, &start, &end,
e6138876 3713 EXTENT_DIRTY, NULL);
5d4f98a2
YZ		 3714
3715 if (ret == 0 && start <= key.objectid) {
b3b4aa74 3716 btrfs_release_path(path);
5d4f98a2
YZ		 3717 rc->search_start = end + 1;
3718 } else {
3173a18f
JB		 3719 if (key.type == BTRFS_EXTENT_ITEM_KEY)
3720 rc->search_start = key.objectid + key.offset;
3721 else
3722 rc->search_start = key.objectid +
3723 rc->extent_root->leafsize;
3fd0a558 3724 memcpy(extent_key, &key, sizeof(key));
5d4f98a2
YZ		 3725 return 0;
3726 }
3727 }
b3b4aa74 3728 btrfs_release_path(path);
5d4f98a2
YZ		 3729 return ret;
3730}
3731
3732static void set_reloc_control(struct reloc_control *rc)
3733{
3734 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
7585717f
CM		 3735
3736 mutex_lock(&fs_info->reloc_mutex);
5d4f98a2 3737 fs_info->reloc_ctl = rc;
7585717f 3738 mutex_unlock(&fs_info->reloc_mutex);
5d4f98a2
YZ		 3739}
3740
3741static void unset_reloc_control(struct reloc_control *rc)
3742{
3743 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
7585717f
CM		 3744
3745 mutex_lock(&fs_info->reloc_mutex);
5d4f98a2 3746 fs_info->reloc_ctl = NULL;
7585717f 3747 mutex_unlock(&fs_info->reloc_mutex);
5d4f98a2
YZ		 3748}
3749
3750static int check_extent_flags(u64 flags)
3751{
3752 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3753 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3754 return 1;
3755 if (!(flags & BTRFS_EXTENT_FLAG_DATA) &&
3756 !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3757 return 1;
3758 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3759 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
3760 return 1;
3761 return 0;
3762}
3763
3fd0a558
YZ		 3764static noinline_for_stack
3765int prepare_to_relocate(struct reloc_control *rc)
3766{
3767 struct btrfs_trans_handle *trans;
3768 int ret;
3769
66d8f3dd
MX		 3770 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root,
3771 BTRFS_BLOCK_RSV_TEMP);
3fd0a558
YZ		 3772 if (!rc->block_rsv)
3773 return -ENOMEM;
3774
3775 /*
3776 * reserve some space for creating reloc trees.
3777 * btrfs_init_reloc_root will use them when there
3778 * is no reservation in transaction handle.
3779 */
4a92b1b8 3780 ret = btrfs_block_rsv_add(rc->extent_root, rc->block_rsv,
08e007d2
MX		 3781 rc->extent_root->nodesize * 256,
3782 BTRFS_RESERVE_FLUSH_ALL);
3fd0a558
YZ		 3783 if (ret)
3784 return ret;
3785
3fd0a558
YZ		 3786 memset(&rc->cluster, 0, sizeof(rc->cluster));
3787 rc->search_start = rc->block_group->key.objectid;
3788 rc->extents_found = 0;
3789 rc->nodes_relocated = 0;
3790 rc->merging_rsv_size = 0;
3fd0a558
YZ		 3791
3792 rc->create_reloc_tree = 1;
3793 set_reloc_control(rc);
3794
7a7eaa40 3795 trans = btrfs_join_transaction(rc->extent_root);
28818947
LB		 3796 if (IS_ERR(trans)) {
3797 unset_reloc_control(rc);
3798 /*
3799 * extent tree is not a ref_cow tree and has no reloc_root to
3800 * cleanup. And callers are responsible to free the above
3801 * block rsv.
3802 */
3803 return PTR_ERR(trans);
3804 }
3fd0a558
YZ		 3805 btrfs_commit_transaction(trans, rc->extent_root);
3806 return 0;
3807}
76dda93c 3808
5d4f98a2
YZ		 3809static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
3810{
3811 struct rb_root blocks = RB_ROOT;
3812 struct btrfs_key key;
3813 struct btrfs_trans_handle *trans = NULL;
3814 struct btrfs_path *path;
3815 struct btrfs_extent_item *ei;
5d4f98a2
YZ		 3816 u64 flags;
3817 u32 item_size;
3818 int ret;
3819 int err = 0;
c87f08ca 3820 int progress = 0;
5d4f98a2
YZ		 3821
3822 path = btrfs_alloc_path();
3fd0a558 3823 if (!path)
5d4f98a2 3824 return -ENOMEM;
026fd317 3825 path->reada = 1;
5d4f98a2 3826
3fd0a558
YZ		 3827 ret = prepare_to_relocate(rc);
3828 if (ret) {
3829 err = ret;
3830 goto out_free;
3831 }
5d4f98a2
YZ		 3832
3833 while (1) {
c87f08ca 3834 progress++;
a22285a6 3835 trans = btrfs_start_transaction(rc->extent_root, 0);
0f788c58
LB		 3836 if (IS_ERR(trans)) {
3837 err = PTR_ERR(trans);
3838 trans = NULL;
3839 break;
3840 }
c87f08ca 3841restart:
3fd0a558
YZ		 3842 if (update_backref_cache(trans, &rc->backref_cache)) {
3843 btrfs_end_transaction(trans, rc->extent_root);
3844 continue;
3845 }
3846
3847 ret = find_next_extent(trans, rc, path, &key);
5d4f98a2
YZ		 3848 if (ret < 0)
3849 err = ret;
3850 if (ret != 0)
3851 break;
3852
3853 rc->extents_found++;
3854
3855 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
3856 struct btrfs_extent_item);
3fd0a558 3857 item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
5d4f98a2
YZ		 3858 if (item_size >= sizeof(*ei)) {
3859 flags = btrfs_extent_flags(path->nodes[0], ei);
3860 ret = check_extent_flags(flags);
3861 BUG_ON(ret);
3862
3863 } else {
3864#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3865 u64 ref_owner;
3866 int path_change = 0;
3867
3868 BUG_ON(item_size !=
3869 sizeof(struct btrfs_extent_item_v0));
3870 ret = get_ref_objectid_v0(rc, path, &key, &ref_owner,
3871 &path_change);
3872 if (ref_owner < BTRFS_FIRST_FREE_OBJECTID)
3873 flags = BTRFS_EXTENT_FLAG_TREE_BLOCK;
3874 else
3875 flags = BTRFS_EXTENT_FLAG_DATA;
3876
3877 if (path_change) {
b3b4aa74 3878 btrfs_release_path(path);
5d4f98a2
YZ		 3879
3880 path->search_commit_root = 1;
3881 path->skip_locking = 1;
3882 ret = btrfs_search_slot(NULL, rc->extent_root,
3883 &key, path, 0, 0);
3884 if (ret < 0) {
3885 err = ret;
3886 break;
3887 }
3888 BUG_ON(ret > 0);
3889 }
3890#else
3891 BUG();
3892#endif
3893 }
3894
3895 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
3896 ret = add_tree_block(rc, &key, path, &blocks);
3897 } else if (rc->stage == UPDATE_DATA_PTRS &&
3fd0a558 3898 (flags & BTRFS_EXTENT_FLAG_DATA)) {
5d4f98a2
YZ		 3899 ret = add_data_references(rc, &key, path, &blocks);
3900 } else {
b3b4aa74 3901 btrfs_release_path(path);
5d4f98a2
YZ		 3902 ret = 0;
3903 }
3904 if (ret < 0) {
3fd0a558 3905 err = ret;
5d4f98a2
YZ		 3906 break;
3907 }
3908
3909 if (!RB_EMPTY_ROOT(&blocks)) {
3910 ret = relocate_tree_blocks(trans, rc, &blocks);
3911 if (ret < 0) {
3fd0a558
YZ		 3912 if (ret != -EAGAIN) {
3913 err = ret;
3914 break;
3915 }
3916 rc->extents_found--;
3917 rc->search_start = key.objectid;
3918 }
3919 }
3920
36ba022a 3921 ret = btrfs_block_rsv_check(rc->extent_root, rc->block_rsv, 5);
3fd0a558 3922 if (ret < 0) {
7654b724 3923 if (ret != -ENOSPC) {
5d4f98a2 3924 err = ret;
3fd0a558 3925 WARN_ON(1);
5d4f98a2
YZ		 3926 break;
3927 }
3fd0a558 3928 rc->commit_transaction = 1;
5d4f98a2
YZ		 3929 }
3930
3fd0a558
YZ		 3931 if (rc->commit_transaction) {
3932 rc->commit_transaction = 0;
3933 ret = btrfs_commit_transaction(trans, rc->extent_root);
3934 BUG_ON(ret);
3935 } else {
3fd0a558 3936 btrfs_end_transaction_throttle(trans, rc->extent_root);
b53d3f5d 3937 btrfs_btree_balance_dirty(rc->extent_root);
3fd0a558 3938 }
5d4f98a2 3939 trans = NULL;
5d4f98a2
YZ		 3940
3941 if (rc->stage == MOVE_DATA_EXTENTS &&
3942 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3943 rc->found_file_extent = 1;
0257bb82 3944 ret = relocate_data_extent(rc->data_inode,
3fd0a558 3945 &key, &rc->cluster);
5d4f98a2
YZ		 3946 if (ret < 0) {
3947 err = ret;
3948 break;
3949 }
3950 }
3951 }
c87f08ca
CM		 3952 if (trans && progress && err == -ENOSPC) {
3953 ret = btrfs_force_chunk_alloc(trans, rc->extent_root,
3954 rc->block_group->flags);
3955 if (ret == 0) {
3956 err = 0;
3957 progress = 0;
3958 goto restart;
3959 }
3960 }
3fd0a558 3961
b3b4aa74 3962 btrfs_release_path(path);
3fd0a558
YZ		 3963 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY,
3964 GFP_NOFS);
5d4f98a2
YZ		 3965
3966 if (trans) {
3fd0a558 3967 btrfs_end_transaction_throttle(trans, rc->extent_root);
b53d3f5d 3968 btrfs_btree_balance_dirty(rc->extent_root);
5d4f98a2
YZ		 3969 }
3970
0257bb82 3971 if (!err) {
3fd0a558
YZ		 3972 ret = relocate_file_extent_cluster(rc->data_inode,
3973 &rc->cluster);
0257bb82
YZ		 3974 if (ret < 0)
3975 err = ret;
3976 }
3977
3fd0a558
YZ		 3978 rc->create_reloc_tree = 0;
3979 set_reloc_control(rc);
0257bb82 3980
3fd0a558
YZ		 3981 backref_cache_cleanup(&rc->backref_cache);
3982 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
5d4f98a2 3983
3fd0a558 3984 err = prepare_to_merge(rc, err);
5d4f98a2
YZ		 3985
3986 merge_reloc_roots(rc);
3987
3fd0a558 3988 rc->merge_reloc_tree = 0;
5d4f98a2 3989 unset_reloc_control(rc);
3fd0a558 3990 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
5d4f98a2
YZ		 3991
3992 /* get rid of pinned extents */
7a7eaa40 3993 trans = btrfs_join_transaction(rc->extent_root);
3612b495
TI		 3994 if (IS_ERR(trans))
3995 err = PTR_ERR(trans);
3996 else
3997 btrfs_commit_transaction(trans, rc->extent_root);
3fd0a558
YZ		 3998out_free:
3999 btrfs_free_block_rsv(rc->extent_root, rc->block_rsv);
4000 btrfs_free_path(path);
5d4f98a2
YZ		 4001 return err;
4002}
4003
4004static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
0257bb82 4005 struct btrfs_root *root, u64 objectid)
5d4f98a2
YZ		 4006{
4007 struct btrfs_path *path;
4008 struct btrfs_inode_item *item;
4009 struct extent_buffer *leaf;
4010 int ret;
4011
4012 path = btrfs_alloc_path();
4013 if (!path)
4014 return -ENOMEM;
4015
4016 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
4017 if (ret)
4018 goto out;
4019
4020 leaf = path->nodes[0];
4021 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
4022 memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
4023 btrfs_set_inode_generation(leaf, item, 1);
0257bb82 4024 btrfs_set_inode_size(leaf, item, 0);
5d4f98a2 4025 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
3fd0a558
YZ		 4026 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
4027 BTRFS_INODE_PREALLOC);
5d4f98a2 4028 btrfs_mark_buffer_dirty(leaf);
b3b4aa74 4029 btrfs_release_path(path);
5d4f98a2
YZ		 4030out:
4031 btrfs_free_path(path);
4032 return ret;
4033}
4034
4035/*
4036 * helper to create inode for data relocation.
4037 * the inode is in data relocation tree and its link count is 0
4038 */
3fd0a558
YZ		 4039static noinline_for_stack
4040struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
4041 struct btrfs_block_group_cache *group)
5d4f98a2
YZ		 4042{
4043 struct inode *inode = NULL;
4044 struct btrfs_trans_handle *trans;
4045 struct btrfs_root *root;
4046 struct btrfs_key key;
5d4f98a2
YZ		 4047 u64 objectid = BTRFS_FIRST_FREE_OBJECTID;
4048 int err = 0;
4049
4050 root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4051 if (IS_ERR(root))
4052 return ERR_CAST(root);
4053
a22285a6 4054 trans = btrfs_start_transaction(root, 6);
3fd0a558
YZ		 4055 if (IS_ERR(trans))
4056 return ERR_CAST(trans);
5d4f98a2 4057
581bb050 4058 err = btrfs_find_free_objectid(root, &objectid);
5d4f98a2
YZ		 4059 if (err)
4060 goto out;
4061
0257bb82 4062 err = __insert_orphan_inode(trans, root, objectid);
5d4f98a2
YZ		 4063 BUG_ON(err);
4064
4065 key.objectid = objectid;
4066 key.type = BTRFS_INODE_ITEM_KEY;
4067 key.offset = 0;
73f73415 4068 inode = btrfs_iget(root->fs_info->sb, &key, root, NULL);
5d4f98a2
YZ		 4069 BUG_ON(IS_ERR(inode) || is_bad_inode(inode));
4070 BTRFS_I(inode)->index_cnt = group->key.objectid;
4071
4072 err = btrfs_orphan_add(trans, inode);
4073out:
5d4f98a2 4074 btrfs_end_transaction(trans, root);
b53d3f5d 4075 btrfs_btree_balance_dirty(root);
5d4f98a2
YZ		 4076 if (err) {
4077 if (inode)
4078 iput(inode);
4079 inode = ERR_PTR(err);
4080 }
4081 return inode;
4082}
4083
a9995eec 4084static struct reloc_control *alloc_reloc_control(struct btrfs_fs_info *fs_info)
3fd0a558
YZ		 4085{
4086 struct reloc_control *rc;
4087
4088 rc = kzalloc(sizeof(*rc), GFP_NOFS);
4089 if (!rc)
4090 return NULL;
4091
4092 INIT_LIST_HEAD(&rc->reloc_roots);
4093 backref_cache_init(&rc->backref_cache);
4094 mapping_tree_init(&rc->reloc_root_tree);
a9995eec
JB		 4095 extent_io_tree_init(&rc->processed_blocks,
4096 fs_info->btree_inode->i_mapping);
3fd0a558
YZ		 4097 return rc;
4098}
4099
5d4f98a2
YZ		 4100/*
4101 * function to relocate all extents in a block group.
4102 */
4103int btrfs_relocate_block_group(struct btrfs_root *extent_root, u64 group_start)
4104{
4105 struct btrfs_fs_info *fs_info = extent_root->fs_info;
4106 struct reloc_control *rc;
0af3d00b
JB		 4107 struct inode *inode;
4108 struct btrfs_path *path;
5d4f98a2 4109 int ret;
f0486c68 4110 int rw = 0;
5d4f98a2
YZ		 4111 int err = 0;
4112
a9995eec 4113 rc = alloc_reloc_control(fs_info);
5d4f98a2
YZ		 4114 if (!rc)
4115 return -ENOMEM;
4116
f0486c68 4117 rc->extent_root = extent_root;
3fd0a558 4118
5d4f98a2
YZ		 4119 rc->block_group = btrfs_lookup_block_group(fs_info, group_start);
4120 BUG_ON(!rc->block_group);
4121
f0486c68
YZ		 4122 if (!rc->block_group->ro) {
4123 ret = btrfs_set_block_group_ro(extent_root, rc->block_group);
4124 if (ret) {
4125 err = ret;
4126 goto out;
4127 }
4128 rw = 1;
4129 }
4130
0af3d00b
JB		 4131 path = btrfs_alloc_path();
4132 if (!path) {
4133 err = -ENOMEM;
4134 goto out;
4135 }
4136
4137 inode = lookup_free_space_inode(fs_info->tree_root, rc->block_group,
4138 path);
4139 btrfs_free_path(path);
4140
4141 if (!IS_ERR(inode))
4142 ret = delete_block_group_cache(fs_info, inode, 0);
4143 else
4144 ret = PTR_ERR(inode);
4145
4146 if (ret && ret != -ENOENT) {
4147 err = ret;
4148 goto out;
4149 }
4150
5d4f98a2
YZ		 4151 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
4152 if (IS_ERR(rc->data_inode)) {
4153 err = PTR_ERR(rc->data_inode);
4154 rc->data_inode = NULL;
4155 goto out;
4156 }
4157
4158 printk(KERN_INFO "btrfs: relocating block group %llu flags %llu\n",
4159 (unsigned long long)rc->block_group->key.objectid,
4160 (unsigned long long)rc->block_group->flags);
4161
eb73c1b7 4162 ret = btrfs_start_all_delalloc_inodes(fs_info, 0);
8ccf6f19
MX		 4163 if (ret < 0) {
4164 err = ret;
4165 goto out;
4166 }
6bbe3a9c 4167 btrfs_wait_ordered_extents(fs_info->tree_root, 0);
5d4f98a2
YZ		 4168
4169 while (1) {
76dda93c 4170 mutex_lock(&fs_info->cleaner_mutex);
5d4f98a2 4171 ret = relocate_block_group(rc);
76dda93c 4172 mutex_unlock(&fs_info->cleaner_mutex);
5d4f98a2
YZ		 4173 if (ret < 0) {
4174 err = ret;
3fd0a558 4175 goto out;
5d4f98a2
YZ		 4176 }
4177
4178 if (rc->extents_found == 0)
4179 break;
4180
4181 printk(KERN_INFO "btrfs: found %llu extents\n",
4182 (unsigned long long)rc->extents_found);
4183
4184 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
4185 btrfs_wait_ordered_range(rc->data_inode, 0, (u64)-1);
4186 invalidate_mapping_pages(rc->data_inode->i_mapping,
4187 0, -1);
4188 rc->stage = UPDATE_DATA_PTRS;
5d4f98a2
YZ		 4189 }
4190 }
4191
0257bb82
YZ		 4192 filemap_write_and_wait_range(fs_info->btree_inode->i_mapping,
4193 rc->block_group->key.objectid,
4194 rc->block_group->key.objectid +
4195 rc->block_group->key.offset - 1);
5d4f98a2
YZ		 4196
4197 WARN_ON(rc->block_group->pinned > 0);
4198 WARN_ON(rc->block_group->reserved > 0);
4199 WARN_ON(btrfs_block_group_used(&rc->block_group->item) > 0);
4200out:
f0486c68
YZ		 4201 if (err && rw)
4202 btrfs_set_block_group_rw(extent_root, rc->block_group);
5d4f98a2 4203 iput(rc->data_inode);
5d4f98a2
YZ		 4204 btrfs_put_block_group(rc->block_group);
4205 kfree(rc);
4206 return err;
4207}
4208
76dda93c
YZ		 4209static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
4210{
4211 struct btrfs_trans_handle *trans;
79787eaa 4212 int ret, err;
76dda93c 4213
a22285a6 4214 trans = btrfs_start_transaction(root->fs_info->tree_root, 0);
79787eaa
JM		 4215 if (IS_ERR(trans))
4216 return PTR_ERR(trans);
76dda93c
YZ		 4217
4218 memset(&root->root_item.drop_progress, 0,
4219 sizeof(root->root_item.drop_progress));
4220 root->root_item.drop_level = 0;
4221 btrfs_set_root_refs(&root->root_item, 0);
4222 ret = btrfs_update_root(trans, root->fs_info->tree_root,
4223 &root->root_key, &root->root_item);
76dda93c 4224
79787eaa
JM		 4225 err = btrfs_end_transaction(trans, root->fs_info->tree_root);
4226 if (err)
4227 return err;
4228 return ret;
76dda93c
YZ		 4229}
4230
5d4f98a2
YZ		 4231/*
4232 * recover relocation interrupted by system crash.
4233 *
4234 * this function resumes merging reloc trees with corresponding fs trees.
4235 * this is important for keeping the sharing of tree blocks
4236 */
4237int btrfs_recover_relocation(struct btrfs_root *root)
4238{
4239 LIST_HEAD(reloc_roots);
4240 struct btrfs_key key;
4241 struct btrfs_root *fs_root;
4242 struct btrfs_root *reloc_root;
4243 struct btrfs_path *path;
4244 struct extent_buffer *leaf;
4245 struct reloc_control *rc = NULL;
4246 struct btrfs_trans_handle *trans;
4247 int ret;
4248 int err = 0;
4249
4250 path = btrfs_alloc_path();
4251 if (!path)
4252 return -ENOMEM;
026fd317 4253 path->reada = -1;
5d4f98a2
YZ		 4254
4255 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
4256 key.type = BTRFS_ROOT_ITEM_KEY;
4257 key.offset = (u64)-1;
4258
4259 while (1) {
4260 ret = btrfs_search_slot(NULL, root->fs_info->tree_root, &key,
4261 path, 0, 0);
4262 if (ret < 0) {
4263 err = ret;
4264 goto out;
4265 }
4266 if (ret > 0) {
4267 if (path->slots[0] == 0)
4268 break;
4269 path->slots[0]--;
4270 }
4271 leaf = path->nodes[0];
4272 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
b3b4aa74 4273 btrfs_release_path(path);
5d4f98a2
YZ		 4274
4275 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
4276 key.type != BTRFS_ROOT_ITEM_KEY)
4277 break;
4278
cb517eab 4279 reloc_root = btrfs_read_fs_root(root, &key);
5d4f98a2
YZ		 4280 if (IS_ERR(reloc_root)) {
4281 err = PTR_ERR(reloc_root);
4282 goto out;
4283 }
4284
4285 list_add(&reloc_root->root_list, &reloc_roots);
4286
4287 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
4288 fs_root = read_fs_root(root->fs_info,
4289 reloc_root->root_key.offset);
4290 if (IS_ERR(fs_root)) {
76dda93c
YZ		 4291 ret = PTR_ERR(fs_root);
4292 if (ret != -ENOENT) {
4293 err = ret;
4294 goto out;
4295 }
79787eaa
JM		 4296 ret = mark_garbage_root(reloc_root);
4297 if (ret < 0) {
4298 err = ret;
4299 goto out;
4300 }
5d4f98a2
YZ		 4301 }
4302 }
4303
4304 if (key.offset == 0)
4305 break;
4306
4307 key.offset--;
4308 }
b3b4aa74 4309 btrfs_release_path(path);
5d4f98a2
YZ		 4310
4311 if (list_empty(&reloc_roots))
4312 goto out;
4313
a9995eec 4314 rc = alloc_reloc_control(root->fs_info);
5d4f98a2
YZ		 4315 if (!rc) {
4316 err = -ENOMEM;
4317 goto out;
4318 }
4319
5d4f98a2
YZ		 4320 rc->extent_root = root->fs_info->extent_root;
4321
4322 set_reloc_control(rc);
4323
7a7eaa40 4324 trans = btrfs_join_transaction(rc->extent_root);
3612b495
TI		 4325 if (IS_ERR(trans)) {
4326 unset_reloc_control(rc);
4327 err = PTR_ERR(trans);
4328 goto out_free;
4329 }
3fd0a558
YZ		 4330
4331 rc->merge_reloc_tree = 1;
4332
5d4f98a2
YZ		 4333 while (!list_empty(&reloc_roots)) {
4334 reloc_root = list_entry(reloc_roots.next,
4335 struct btrfs_root, root_list);
4336 list_del(&reloc_root->root_list);
4337
4338 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
4339 list_add_tail(&reloc_root->root_list,
4340 &rc->reloc_roots);
4341 continue;
4342 }
4343
4344 fs_root = read_fs_root(root->fs_info,
4345 reloc_root->root_key.offset);
79787eaa
JM		 4346 if (IS_ERR(fs_root)) {
4347 err = PTR_ERR(fs_root);
4348 goto out_free;
4349 }
5d4f98a2 4350
ffd7b339 4351 err = __add_reloc_root(reloc_root);
79787eaa 4352 BUG_ON(err < 0); /* -ENOMEM or logic error */
5d4f98a2
YZ		 4353 fs_root->reloc_root = reloc_root;
4354 }
4355
79787eaa
JM		 4356 err = btrfs_commit_transaction(trans, rc->extent_root);
4357 if (err)
4358 goto out_free;
5d4f98a2
YZ		 4359
4360 merge_reloc_roots(rc);
4361
4362 unset_reloc_control(rc);
4363
7a7eaa40 4364 trans = btrfs_join_transaction(rc->extent_root);
3612b495
TI		 4365 if (IS_ERR(trans))
4366 err = PTR_ERR(trans);
4367 else
79787eaa 4368 err = btrfs_commit_transaction(trans, rc->extent_root);
3612b495 4369out_free:
3fd0a558 4370 kfree(rc);
3612b495 4371out:
aca1bba6
LB		 4372 if (!list_empty(&reloc_roots))
4373 free_reloc_roots(&reloc_roots);
4374
5d4f98a2
YZ		 4375 btrfs_free_path(path);
4376
4377 if (err == 0) {
4378 /* cleanup orphan inode in data relocation tree */
4379 fs_root = read_fs_root(root->fs_info,
4380 BTRFS_DATA_RELOC_TREE_OBJECTID);
4381 if (IS_ERR(fs_root))
4382 err = PTR_ERR(fs_root);
d7ce5843 4383 else
66b4ffd1 4384 err = btrfs_orphan_cleanup(fs_root);
5d4f98a2
YZ		 4385 }
4386 return err;
4387}
4388
4389/*
4390 * helper to add ordered checksum for data relocation.
4391 *
4392 * cloning checksum properly handles the nodatasum extents.
4393 * it also saves CPU time to re-calculate the checksum.
4394 */
4395int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
4396{
4397 struct btrfs_ordered_sum *sums;
4398 struct btrfs_sector_sum *sector_sum;
4399 struct btrfs_ordered_extent *ordered;
4400 struct btrfs_root *root = BTRFS_I(inode)->root;
4401 size_t offset;
4402 int ret;
4403 u64 disk_bytenr;
4404 LIST_HEAD(list);
4405
4406 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
4407 BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
4408
4409 disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
4410 ret = btrfs_lookup_csums_range(root->fs_info->csum_root, disk_bytenr,
a2de733c 4411 disk_bytenr + len - 1, &list, 0);
79787eaa
JM		 4412 if (ret)
4413 goto out;
5d4f98a2
YZ		 4414
4415 while (!list_empty(&list)) {
4416 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
4417 list_del_init(&sums->list);
4418
4419 sector_sum = sums->sums;
4420 sums->bytenr = ordered->start;
4421
4422 offset = 0;
4423 while (offset < sums->len) {
4424 sector_sum->bytenr += ordered->start - disk_bytenr;
4425 sector_sum++;
4426 offset += root->sectorsize;
4427 }
4428
4429 btrfs_add_ordered_sum(inode, ordered, sums);
4430 }
79787eaa 4431out:
5d4f98a2 4432 btrfs_put_ordered_extent(ordered);
411fc6bc 4433 return ret;
5d4f98a2 4434}
3fd0a558
YZ		 4435
4436void btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
4437 struct btrfs_root *root, struct extent_buffer *buf,
4438 struct extent_buffer *cow)
4439{
4440 struct reloc_control *rc;
4441 struct backref_node *node;
4442 int first_cow = 0;
4443 int level;
4444 int ret;
4445
4446 rc = root->fs_info->reloc_ctl;
4447 if (!rc)
4448 return;
4449
4450 BUG_ON(rc->stage == UPDATE_DATA_PTRS &&
4451 root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID);
4452
4453 level = btrfs_header_level(buf);
4454 if (btrfs_header_generation(buf) <=
4455 btrfs_root_last_snapshot(&root->root_item))
4456 first_cow = 1;
4457
4458 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
4459 rc->create_reloc_tree) {
4460 WARN_ON(!first_cow && level == 0);
4461
4462 node = rc->backref_cache.path[level];
4463 BUG_ON(node->bytenr != buf->start &&
4464 node->new_bytenr != buf->start);
4465
4466 drop_node_buffer(node);
4467 extent_buffer_get(cow);
4468 node->eb = cow;
4469 node->new_bytenr = cow->start;
4470
4471 if (!node->pending) {
4472 list_move_tail(&node->list,
4473 &rc->backref_cache.pending[level]);
4474 node->pending = 1;
4475 }
4476
4477 if (first_cow)
4478 __mark_block_processed(rc, node);
4479
4480 if (first_cow && level > 0)
4481 rc->nodes_relocated += buf->len;
4482 }
4483
4484 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS) {
4485 ret = replace_file_extents(trans, rc, root, cow);
4486 BUG_ON(ret);
4487 }
4488}
4489
4490/*
4491 * called before creating snapshot. it calculates metadata reservation
4492 * requried for relocating tree blocks in the snapshot
4493 */
4494void btrfs_reloc_pre_snapshot(struct btrfs_trans_handle *trans,
4495 struct btrfs_pending_snapshot *pending,
4496 u64 *bytes_to_reserve)
4497{
4498 struct btrfs_root *root;
4499 struct reloc_control *rc;
4500
4501 root = pending->root;
4502 if (!root->reloc_root)
4503 return;
4504
4505 rc = root->fs_info->reloc_ctl;
4506 if (!rc->merge_reloc_tree)
4507 return;
4508
4509 root = root->reloc_root;
4510 BUG_ON(btrfs_root_refs(&root->root_item) == 0);
4511 /*
4512 * relocation is in the stage of merging trees. the space
4513 * used by merging a reloc tree is twice the size of
4514 * relocated tree nodes in the worst case. half for cowing
4515 * the reloc tree, half for cowing the fs tree. the space
4516 * used by cowing the reloc tree will be freed after the
4517 * tree is dropped. if we create snapshot, cowing the fs
4518 * tree may use more space than it frees. so we need
4519 * reserve extra space.
4520 */
4521 *bytes_to_reserve += rc->nodes_relocated;
4522}
4523
4524/*
4525 * called after snapshot is created. migrate block reservation
4526 * and create reloc root for the newly created snapshot
4527 */
49b25e05 4528int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
3fd0a558
YZ		 4529 struct btrfs_pending_snapshot *pending)
4530{
4531 struct btrfs_root *root = pending->root;
4532 struct btrfs_root *reloc_root;
4533 struct btrfs_root *new_root;
4534 struct reloc_control *rc;
4535 int ret;
4536
4537 if (!root->reloc_root)
49b25e05 4538 return 0;
3fd0a558
YZ		 4539
4540 rc = root->fs_info->reloc_ctl;
4541 rc->merging_rsv_size += rc->nodes_relocated;
4542
4543 if (rc->merge_reloc_tree) {
4544 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
4545 rc->block_rsv,
4546 rc->nodes_relocated);
49b25e05
JM		 4547 if (ret)
4548 return ret;
3fd0a558
YZ		 4549 }
4550
4551 new_root = pending->snap;
4552 reloc_root = create_reloc_root(trans, root->reloc_root,
4553 new_root->root_key.objectid);
49b25e05
JM		 4554 if (IS_ERR(reloc_root))
4555 return PTR_ERR(reloc_root);
3fd0a558 4556
ffd7b339
JM		 4557 ret = __add_reloc_root(reloc_root);
4558 BUG_ON(ret < 0);
3fd0a558
YZ		 4559 new_root->reloc_root = reloc_root;
4560
49b25e05 4561 if (rc->create_reloc_tree)
3fd0a558 4562 ret = clone_backref_node(trans, rc, root, reloc_root);
49b25e05 4563 return ret;
3fd0a558 4564}
Linux 6.x block layer and io_uring tree(s)